My suggestion would be to buy two good bookshelf speakers that you could use as surrounds later on when you get a better situation for home theater. I would look for deals on receivers on craigslist. I see lots of good deals for receivers on craigslist, you can get a good used receiver for 50 to 60 dollars that would be suitable for your situation. You will be doing a lot of near-field listening so you don't need a lot of watts per channel, I am guessing 50 will do fine.
A couple of speaker packages I would recommend are:
2 Hsu HB-1
speakers and a STF1 sub
2 Elemental Designs A3-5TC
speakers and a A3-250
sub (use their home theater package builder
to get this under $500)
Between those packages, I think the Hsu probably has much better speakers but the ED has a more formidable sub. Something else you can do is get the Hsu performance 1 Package
, this is almost ideal for surround sound in a dorm room situation, but you would want to sell it later on when you get more room for a serious setup. Something else that looks pretty good for your situation is the tweakcity Gizmo/WAF package
. Add to that a Hsu STF1 sub and you will have a pretty good sounding setup. And to be honest, if you are only going to listen at modest volumes, you don't really need a sub.
There are other subs and speakers which are worth looking at in yoru situation, but I would definitely turn to ebay and craigslist for the receiver. Some other subs to consider are the Bic Acoustech Cinema Series H100, the Premier Acoustic PA-120W, the Bic America VK-12, the Bic Acoustech New Model Platinum Series PL-200, the Dayton ES10 Elite Series, and the BIC Venturi V1220. Some other speakers to look at are the Behringer truth 2030p or 2031p, the Infinity Primus p162, TSC TSBL 6.5
, and the SVS SBS or SCS speakers. Those will be inexpensive and make room in your budget for the sub and receiver. Also take a look at The Speaker Companies
other stuff, that have lots of inexpensive speakers.