Best Paint for Foam?

[The Count]

Hi, my family members are working on somewhat of a project involving foam material. They're having trouble with the paint purchased to turn it the desired color. I'm hoping that posting here will turn up some leads to what kind of paints they can buy to make sure their foam products end up as professional-looking as possible. The type of foam they're working with is sponge foam if that makes a difference. So I'll wait for replies to then inform them what the best paint to get would be.

Thanks for your help with this endeavor.