The size of an adult boa depends first on the species of boa and then the gender. There are smaller boas and then there are bigger boas and you can learn more about them in the Boa section. =)

If, however, cost maintenance is an issue, corns make a great addition as they are generally less expensive, have easier husbandry requirements and eat smaller, cheaper prey. I love my orangey boy and I'd say he's the easiest of the four species I keep to take care of (not like any of them are hard...but there are differences). =)