Im usually a pretty good researcher and to be honest, pride myself on it but I gotta tell ya .... trying to shop for backpacking gear is really starting to make my head spin and I think I need some advice before I end up making any more purchases that end up not being what I need

So this is the equipment Ive purchased so far. Most of the time Ill be up here in high elevations, but will be using this stuff everywhere, lower elevations and even the desert if possible. From what Ive read, it sounds like if you want to be out during winter, its probably best to have two sets of gear. So for this first set Im looking to 3 season equipment.
1. A slumberjack 2 tent. This was my first purchase and admittedly a misinformed purchase. The tent weighs just under 7 lbs and I now realize thats pretty dam heavy. Whats more, I paid $69 for it and thanks to the threads here I see many tents for under $100 that weigh half the weight. I did set it up in a thunderstorm the other night and it worked well. I do like that it has enough room for my GF and I, and a decent sized dog as well. What do you guys think? Scrap it and buy a lighter version or suck it up and pack the 7 lbs around?
2. I found a coleman exponent canyon mummy 32 degree bag on craigslist for $50. I did a couple quick searches and it seems like a good bag. Weighing at just over 2 lbs and being rated well. My first search showed a sales price of $189, the second for $169 so I figured at $50 thats a buy! I go buy it, get home and immediately find one brand new online for $59. Grrreeeeaaat. I still need another bag though, so I wouldnt mind any input on this bag. I might just buy a new one for $59. Im not sure about the $150+++ bags and/or if I want to drop the cash right now.
3. I bought a snow peak trekker kit that consists of the gigapower stove, the snow peak titanium 1400 cookset, and a windshield. Heres the link: http://www.campsaver.com/trekker-kit
So, I wouldnt mind any input on these items and whether or not I should ditch them or keep em. I think Im happy with the cook set, and the sleeping bag as well other then the fact I got burnt on price. The tent is fine but its heavy.
Also I need advise on footwear, and packs as well. Would rather have a boot of some sort or a taller type shoe I believe. Definitely not interested in sandals.
Thanks in advance. Ill still be reading and researching.... but if someone could point me in the right direction Ild be greatful. Price is an issue, but I can spend the dough if its one of those make or break items. I think on most Items Im looking for the standout price/performance winner in each category..... regardless of what that price might be.