Flash based cartridges could be quite cheep to produce in quantities. It's not 1990, heck with such low prices on 1-2GB flash NAND's and moderate volume on PCB production and a piece of plastic shell I can not see why prices should have to be super high.
But hey anyways even if prices should be high I personally don't see any problem since I pay those prices for games today. Just because it targets early to mid 90s hardware specs doesn't mean it's not worth the money. I mean I still play games that are 25+ years old, it's not all about em graphics, a new system with some old school goodness would be really nice
Cross my fingers this project works out.
