It sounds like the main issue here is cost right? I was really poor in college so that would have been my number one as well.

A lot of good, lightweight stuff can be fairly inexpensive. Unfortunately a sleeping bag is not one. You might want to borrow or rent until you can afford a nice one. Alternatively if you have access to a sewing machine you can make a nice quilt for little money. Take a look at Ray Jardine's page and get a quilt kit.

As far as clothes go here is something that may help. You may never have had good camping clothes but perhaps you did some running? Running clothes are synthetic and have good wicking properties so they make good hiking clothes. Running shoes are fine for backpacking in also.