I haven't used a tarp since I was a kid, I'm happy with my GG TheOne tent, although I did have some issues with it standing up to sustained downpours last year on the CT.
For your budget, and since you're undecided on tent vs tarp set-up, I would also recommend becoming a BPL membr and checking out the gear swap forum, even posting an ad for some of the things you're looking for. No need to spend so much on all new gear. Try out a few things and you can always resell what doesn't work for you.
Also, +1 on wind pants rather than rain pants. the top is more important for rain gear. Checkout Montbell stretch wind pants and some or their rain jackets, or also Montane for jackets. Their prices aren't bad and the weight is reasonable also.