I would agree that going to all the bike shops to test ride what bikes are in your price range. Now adays there seems to be a split between quality bikes for people who are going to be dedicated riders and those that only want something to mess around with. You can get a bike for less than $150 with dual suspension if you don't care about material or maker. But if you want a bike to ride off road with any regularity then you will have to go to a shop and test the market. Nowadays you should be able to get something similiar, maybe a little less, than what I list below for the money you were talking about.
You may also want to consider purchasing a good used bike. For example, I am still riding my M400 Aluminum frame by Raleigh that I purchased 4 years ago for around $800. I got it with clipless pedals, cantalever breaks, shimano shifters etc., gel saddle and so on. It was about midway in the racing class (don't let that fool you, "racing" generally means higher quality components and NOT that the bike is only for those who intend to race) and would likely consider selling it in the near future for about half what I paid. It still looks great and with the aluminum frame and front susupension the bike rocks. I am a serious biker though and thinking about jumping up to a titanium frame bike.
Good luck.