I have bought many bows off Ebay, and have generally been well pleased. Be sure to check out the feedback of the seller, though. I recently got a 6 month old Bowtech for about $300 less than list price new. A Bowtech Pro 38 or 40 would be a good choice for your draw length. The used Hoyts can be had at a resonable used price, and sometimes they will have all the accessories that you need already on the bow. You can often get a really good deal on bows with accessories. One thing you have to watch with Hoyts is that some sellers either don't know the actual draw length range of the bow/cam, or perhaps intentionally overstate it. The Redline cam for instance only has 1" of draw length adjustment. The Ultratec, Protec, as well as some excellent older models like the Defiant will be available in your draw length. Mathews bows are more difficult to get in your price range, although I have gotten two in the 325-400 range, but that was bare bow. They are also not draw length adjustable to any extent except for the original Max-Cam bows like the Conquest. A Mathews Conquest or
Q2 XL would be available in 31" draw. Also, some "off brands" are available for less $, and are very good bows. I recently bought and sold a McPherson 38 Special that was a very quiet, low recoil, accurate bow, very similar in shooting characteristics to a Mathews Q2 XL. PSE makes a few bows that come in your draw length. Lately, I have seen a few shop owners trying to clear out their inventories by selling unused PSE bows on ebay. You can save a lot of money that way. Is there any possibility that a pro-shop or 2 in your area has used bows? Perhaps they might know of some customers who have ordered a new bow, and have excellent used bows that they might want to sell. That way, you might be able to actually shoot the bow before you buy it. Just a thought. You actually have a lot of options here. The good part of all of this is that, IMO, there really isn't that huge a difference between different brands of bows. Almost all makes of bows can be tuned to shoot better than the archer can shoot. Try not to get too frustrated by all of the brands, models, of wanting to shoot only the top of the line bows. You will be able to shoot well with most any well-fitted bow you get, and then you can start to enjoy the sport of archery! Good Luck!