Maybe, maybe not. We've found some insane local Craigslist deals on adult boas and retics, and on enclosures for them, because people need to sell them fast (job loss, landlord freaked out or moving into a place where snakes aren't allowed, etc), and shipping big snakes and large enclosures can cost more than what you're buying.
Throw in "live feeder only" on a 10' snake and the price will have to be low because you can't feed it one (relatively) inexpensive 3# rabbit, it's way too dangerous, you're looking at 2-3 1# rabbits per feeding, plus travelling to get them several times a month if you don't raise your own.