Generally your GFXs look alright, but I’d be concerned with the lighting and pricing … everything seems too bright (especially the first render)
As for the pricing, I believe 500 Robux is just way overpriced for a start. You’d have to convince users to purchase your product for a lower price & why they shouldn’t turn to other GFX creators such as myself, on top of that I charge well under 200 Robux for my variety of GFX designs so I’m not sure how you plan to attract customers who’re willing to pay 500 Robux for a GFX.
So again, your GFXs are pretty good especially in posing, but it needs work in lighting. As for the pricing you really need to keep it low for a start and gradually increase it over time (e.g. I increase my prices by ~10 Robux every 3-6 months)