I agree with jaiden about the tarp. Tents are pretty expensive and don't do much that a tarp won't do (there are cheap tents but they tend to be heavy). However it depends a bit on where you are going. If there are lots of trees then do the tarp because you'll be able to pitch it using trees. If trees are fewer or farther between then the tarp is a little problematic unless you have trekking poles (you didn't mention whether you were planning on using those). If you add the price of the trekking poles then the tarp/poles combination is right up there with a good tent again.

Packs can be expensive also but they needn't be if you can go lightweight on what you put in them. The expensive packs are built to carry heavy loads and have all kinds of features for distributing this weight in the best way. If you learn to go lightweight with your gear then
a good lightweight pack needn't cost much. Take a look at Gossamer Gear. Their packs are all less than $150 and and weigh very little. They are really nice IMHO. Get one of those and a basic 8x10 tarp from campmor with some tent stakes and guylines and some plastic dropcloth for a groundcover and you are set for about $200.