To reiterate to the Original Poster what FinallyME said, The bag really *is* where you want to spend your money.

if I had 500 dollars to outfit myself completely for a trip I would be spending 400 of it on a high end western mountaineering down bag, and cobbling the rest together from used gear and the thrift store.. I'm dead serious. and I backpack a lot

Just about everything else you can make, modify or put together easy perfectly good lightweight items easily. Sleeping bags really are "light, warm, inexpensive - pick two".

When I get newbs into the sport the first thing I get them to buy are good boots/shoes that work for them. Then I encourage them to get a good sleeping bag and borrow gear from me for the rest until they aquire their own.