Considering you get charged for the campaigns, I don't even think cosmetic items should be for sale. It isn't as if this game is a MOBA, where you get access to everything (the game modes) EXCEPT all the skins.
Smite has way more characters than Raiders, and waaaaaaaaaaaay more skin variation. They also have premium skins and alternate colors, as well as mastery skins.
If Raiders could ramp up the skin variety, and include a bunch of skins you can buy with tickets or gold, then have real money skins for cash (but then those skins should be more special than just looking different. They should, at least, change the way your character ability looks.
Similar to how Poseidon, from Smite, will have different versions of the Kraken ultimate appear depending on the tier-4 skin you're using.
That being said, I think those skins should stay within the realm of $5-8 US. Why? Probably because the ENTIRE DLC, THE CHARACTERS THEY UNLOCK, AND THE FREAKING WEAPONS THEY ALLOW YOU TO UNLOCK cost $10.
I also think $10 per DLC, considering what you get, is fairly reasonable. Since this isn't exactly a long drawn out game with a lot to do and explore. You're forced to do PvP or at least co-op to make any progress and are tethered to queue times, shoddy MMR mechanics, dealing with antagonists, RNG, and repetitive objectives.
A game like SFV was charging like $3-5 US per skin. A game like Injustice gave you all the customization items for free, but sold character packs or characters themselves for cash. A game like Paragon had skins for $5-15 US, but was also giving them away for free in loot boxes you could win all the time from playing the game.
I think the solution is to add alternate colors of the default skins, make them purchasable with gold/tickets, and then bring down the price of new textures to $5-8 dollars. I'd be tempted to spend money that way. There is no realm where I would spend $20 or $30 for a damn skin. That is insanity. I don't give a shit how much work it took to do. One skin costs more than all DLCs and the 3 characters you unlock - as well as all the weapons you can get from the DLCs? Nah.
My guess is they keep the skins that high because someone will invariably buy it. There are always people with tons of expendable income. But it looks really greedy and opportunistic to players that exercise caution when companies look like they wanna pull a fast one on you.
Then they have sales to bring the price down to more reasonable levels and capitalize on sales-mentality, where people opt to purchase skins because they're normally so damn expensive.