I buy bows the same way I buy other expensive items like vehicles and optics - used! I love it when guys sell a perfectly good bow a year old; it saves me a lot of money I can spend on actual hunting.
But honestly, I don't replace my bow very often. I just don't see the point, since advances in technology are rarely revolutionary enough to make a significant difference in my hunt, despite what the manufacturer's say.
In fact, just about anything I can buy used or as a sample item, I will, though it has to be in great shape. Even better than saving money on a purchase is just not buying a new whatever except when you really need to.