I paid 150$ to rescue my 9 year old female (who was recently adopted by a breeder friend who I know will take excellent care of her!). I had no idea what condition she was in (damned internet ads...) but couldn't turn her away when I saw her. Knowing I saved her from a horrible life was worth the lost money.
Realistically, you buy it for 80$. Flip the tank for 30-40$ and you've just picked up snakes at 20-25$ a piece. Worth it in my books!