I looked at every skin from the champions Aatrox-Fizz (That's why there is A-F in the title)
To know when a skin is too expensive or too cheap is taken from Riot's official Guide to Skin Price Tiers.
750 rp: A simple costume change.
975 rp: more immerse qualities than just a costume change.
1350 rp: Changes that bring the idea of the skin to life.
1820 rp: A complete reimagination of the champion with everything changed.
2775/3250 rp: Skins that bring new stuff into the game that was never seen before.
I also used these two pages to help me do my work: League of Legends Wikia and Strategy Zero, where I could find detailed information about the skins.
If I wasn't sure where the skin belongs in the pricecategory I used my own judgement.
If you don't want to read through all of this I will put a List at the end.
When comparing Justicar Aatrox to Blood Moon/Mecha Aatrox, you will notice the price difference. JA offers the same as BMA and MA, so the question is, if JA is underpriced or BMA and MA overpriced.
Dynasty Ahri is currently priced at 975 rp while the only new things she offers are a new model and a new dance animation, which won't be noticed by those who own the skin anyways.
Akali's Infernal skin is clearly underpriced with 520 rp, since it offers far more than just a remodel, that skin could easily be a 975 rp skin.
Her All-star skin on the other hand only offers a re-model and costs too much with 975 rp.
Nurse Akali only brings new syringes that she throws when using her Q, so her price of 975 rp might be debatable.
The only Skins which's price sticks out are Matador Alistar with a simple modelchange but a high price of 975 rp
and Infernal Alistar, who has a new model some new particles on his Q, so again, like with Akali, his price of 975 rp might not be justified.
Nothing that sticks out here.
Everything's fine here too.
Annie in Wonderland certainly is overpriced with it's 1820 rp, since it only offers new models for her and tibbers and with only that, it can't truly be a well translated fantasy of this skin, since the fire doesn't fit in it at all. It should be a 750 rp skin.
Reverse Annie only offers new models and for a 975 rp skin that certainly isn't enough.
Same goes for FrankenTibbers Annie.
Queen Ashe does offer a new model and new white particles for her attacks and abilities, but is that enough for it to be a 975 rp skin? Because the same thing with the white particles was done with Freljord Ashe and that skin only costs 520 rp.
Same goes for Amethyst Ashe with purple particles on her spells and basic attacks.
He's pretty new (lul), so he doesn't have that many skins.
Nothing that stands out here.
He's cool too.
Piltover Customs Blitzcrank might be overpriced with 1350 rp and should rather be a 975 rp skin, because it certainly doesn't offer as much as other epic skins.
Nothing to see here.
He's a chill dude.
Safari Caitlyn is overpriced with 975 rp due to only having a modelchange and nothing else.
Same with Officer Caitlyn. (Btw, that skin is terribly oversexualized, maybe that's why it's 975 rp, cause Riot knows you're gonna buy it anyways.)
Headhunter Caitlyn has translated it's fantasy so well and changed her so much, it could easily be an epic skin (1350 rp).
Her Skins seem to be priced fairly.
Mythic Cassiopeia is overpriced with 975 rp when you compare it to other skins of her, Siren Cassiopeia and Desperada Cassiopeia are both priced at 520 rp and do a good job at delivering their idea.
Mythic Cassiopeia, in comparison to those skins, offers a new scary face when you press R and that's it, it is not really explained why that happens and how it is connected to the skin.
So it should rather be a 750 rp skin.
Gentleman Cho'Gath clearly isn't a legendary skin (1820 rp) to our current standards, but rather a 975 rp skin, since it gives us a new model and fitting new voice lines to the fantasy it's trying to deliver, which I think are very well done.
Jurassic Cho'Gath's price of 975 rp is debatable, since he offers a new model and some new animations and particles of his laugh and two of his spells.
Ice Toboggan Corki is an 1820 rp skin, although it only has a new model for his copter and new textures for corki himself. Certainly just a 750 rp skin.
Red Baron Corki is an 1820 rp skin aswell and also only offers a new model for his copter and new textures for Corki. Although it has new propeller sounds, it's hardly enough to make it a 975 rp skin and even with that it should be 750 rp skin.
Dragonwing Corki has done so much to make the skin feel real and deserves to be an 1350 rp skin.
Lord Darius merely gives us a fancy costume and is not worth 975 rp.
She has good, price-worthy skins.
Corporate Mundo is at maximum an 1350 rp skin; at minimum a 975 rp skin, since there aren't enough changes for it to be an 1820 rp skin.
Mundo Mundo should be a 750 rp skin, because only adding one new sound for the Q isn't enough to make it a 975 rp skin.
Rageborn Mundo's Price could be debated over, since it does offer two new animations and a new model for him and his cleaver, but is that already enough to make it a 975 rp skin?
Soul Reaver Draven doesn't offer enough to be an 1350 rp skin, but rather a 975 rp skin. He barely has new stuff; no new animations, some new particles and a processed voice-over.
Primetime Draven should have a much higher price than 975 rp, but since it's a 'special' Skin like Surprise Party Fiddlesticks, it will probably stay at that low price anyways.
Pool Party Draven offers a lot for a 975 rp skin and comes close to a 1350 rp skin (Debatable).
Sandstorm Ekko put so much heart into it's idea that it could easily be an 1350 rp skin instead of a 975 rp skin, because there's really a lot put into this skin.
Super Galaxy Elise could be a 975 rp skin instead of an 1350 rp skin, because when compared to her other skins, she doesn't bring that much new stuff.
Shadow Evelynn with a price of 520 rp does a really good job at transfering a vampirey feeling of her, she has new particles and a new recall animation + new sounds for it, this skin should be a 975 rp skin for all it has.
His SSG Skin doesn't offer as much as other 1350 rp skins from him and with that it should be a 975 rp skin. (Debatable)
Surprise Party Fiddlesticks, as mentioned before, is a special skin that is a legendary, but still only costs 975 rp, it's special in some way.
When comparing Risen Fiddlesticks (1350 rp) with Dark Candy Fiddlesticks (975 rp) you can see, how much more DCF offers than RF, it should certainly be cheaper (975 rp).
Headmistress Fiora's price of 975 rp is hard to put in the right price-category, since it doesn't show us that much more than her new model. She has new ruler-smacking sounds and a new animation for her taunt. It'd probably fit better in the 750 rp pricecategory.
The only change that was made to supposedly make Fisherman Fizz a 975 rp skin is his R. It does not help to deliver the feel of a fisherman when the shark gets removed for another sea creature that makes new noises (Although a normal fish would have been more fitting than a shark I suppose). It should be a 750 rp skin.
Too expensive skins:
All-Star Akali (975->750)
Matador Alistar (975->750)
Annie in Wonderland (1820->750)
Reverse Annie (975->750)
FrankenTibbers Annie (975->750)
Safari Caitlyn (975->750)
Officer Caitlyn (975->750)
Mythic Cassiopeia (975->750)
Gentleman Cho'Gath (1820->975)
Ice Toboggan Corki (1820->750)
Red Baron Corki (1820->975/750)
Lord Darius (975->750)
Corporate Mundo (1820->1350/975)
Mundo Mundo (975->750)
Soul Reaver Draven (1350->975)
Super Galaxy Elise (1350->975)
SSG Ezreal (1350->975)
Debatable skin prices:
Dynasty Ahri (975->750)?
Nurse Akali (975->750)?
Infernal Alistar (975->750)?
Queen Ashe (975->750)?
Amethyst Ashe (975->750)?
Piltover Customs Blitzcrank (1350->975)?
Jurassic Cho'Gath (975->750)?
Rageborn Mundo (975->750)?
Pool Party Draven (975->1350)?
Sandstorm Ekko (975->1350)?
Risen Fiddlesticks (1350->975)?
Headmistress Fiora (975->750)?
Fisherman Fizz (975->750)?
Too cheap skins:
Infernal Akali (520->975)
Headhunter Caitlyn (975->1350)
Dragonwing Corki (975->1350)
Primetime Draven (975->1350/1820) (It's too cheap on purpose)
Shadow Evelynn (520->975)
Surprise Party Fiddlesticks (975->1350/1820) (Cheap on purpose)
Should I continue this list and judge the other champion skins from G-Z?
Please tell me what you think I missed or where my judgement was wrong in your opinion.