Hello,
Actually Achat pays the developers for their creations and if requested the developer himself can decide the selling price otherwise Achat determines it.
Generally Achat pays, in a one-time payment, in A $, an amount ranging from 7,000 to 10,000A $. (35 € -50 €)
It also gives you the option to enter the dress (or pose) into the personal developer console where the profit will be determined by sales. In that case the developer can choose to redeem the amount in A $ or real money.
Asking to have the opportunity to have your own creation even for free, I think it is a request that would lead to useless work and that would take time away from other far more important requests.
I want to remind you that a dress that costs $ 300A in real money is an amount that varies between € 1.5 and € 2.
The conclusions are up to you.
Personally, I would eliminate the one-time payment and keep only the one based on sales as it would increase the quality of the clothes sent.