Kate,
First of all thanks for saving this little guy ( or girl ) from the pet shop life ! This boa should be treated the same as a columbian red-tail boa baby. The big diffrence is that the species that you have aquired is a smaller boa type. It should max out about 5-6 ft and approx the size of a baseball or softball ( depending on how you feed ). Respect should also be given to this little one since it is probably stressed to the max after being in the pet store. If it was me I would get a ten gallon aquarium for now and buy one of the decently priced UTH ( under tank heater ) with a rheostat on it and place it at one end of the tank. But make sure it only covers about 1/3 of the bottom since you want a cool spot for the boa. Keep the cool end temps around 81-83 and set the UTH at 90. A light is not really needed except for cosmetic reasons. If this is your only boa I would buy a flourescent light since they do not emit much heat a really bring out nice colors. I would also buy a small piece of drift wood for climbing and most definately a hide box. Try not to let the temps fall below 77 on the cool side at night or you could end up with a problem. Wait a few days before feeding a live hopper mouse or adult mouse depending on the size of the snake. Please do not hesitate to call me at 469-363-0635 with any questions that you may have.
Thanks,
Wyatt
TW Intl Inc.
Dallas, Tx