There's no such thing as a red footed box turtle. Are you wanting to buy a box turtle that has colorful red legs? The male three toe box turtles (Terrapene carolina triunguis) sometimes has colorful front legs.
Or are you looking to buy a redfooted tortoise? Most often RF tortoises have yellow dots on the front legs but occasionally you can find red ones. If you look for a cherry head RF tortoise, they have a lot of red on them.
Care is the same as a Redfoot. There is a few good breeders right here on this site. In fact I've got a Cherryhead egg coming at the end of this month!