Having the latest and greatest tech can sometimes come at a price. For instance, subwoofers can cause quite the ruckus if not controlled properly. Investing in a couple of foam panels can help avoid a situation where neighbors are banging on your walls every time you fire up a movie.
You probably don't need industrial grade materials to get the job done, but it's not a bad idea to check out your local home theater shop to see what's available. The normal price range for a single sound panel is roughly $80-$160 each.
An alternative is to build your own using materials found at Lowes, Home Depot, or your local hardware store. While it's not perfect, investing in a little sound dampening and sacrificing some wall space can go a long way in keeping your neighbors happy while freeing you to enjoy that lovely home theater equipment you've invested your hard earned dollars in.