I really agree with Ichiro. Honest feedback and watching real people test-play it is a good idea. Buy some pizzas for gamers you find on craigslist, watch them play and get feedback and make adjustments. Though this is pretty standard for releasing a game, maybe you've already done this step.

Some tactics for low budget game marketing: It might be worth buying some ad banner time on a website community that uses games like yours. Send free promo copies to game magazines and websites. Try to get an exclusive. Get people talking about it.