They prefer ventilated enclosures with low humidity per this care sheet: Josh's Frogs How-To Guides » Blog Archive » Bumble Bee Toad Care and Breeding. Josh also sells them in singles or groups and he is a member here.
In regards to heating; should not use reptile under tank heaters because frogs bury themselves to cool down. You can use the mats on the side, but they are pretty inefficient. I like the ceramic heat lamps, used in conjunction with a thermostat (if room temperature is variable) or a rheostat (if temp is steady). Can also use incandescent red bulbs to provide heat 24 hours/day. Good luck!