You need to ask yourself if you want to buy a complete entry level system at one time, or slowly build a quality system.
You could start with a pair of bookshelf speakers and a receiver for about 300, and then add to the system as funds come available. If you go this route, you have the opportunity to buy used, refurb, and clearance gear as it pops up. I think that most of us would recommend this route.
If you decide to buy everything at once, your best bet is a HTIB (home theater in a box), from the likes of Yamaha or Onkyo. Don't be afraid to get something a year or two old in order to meet your price point. Avoid anything with a built in DVD/Blu-ray player. One system you should consider is the Onlyo HT-S340, it retails for $380.