Getting Started...
As for me, I would start with brogans. As Mr. Wadswworth said, you'll have a difficult time borrowing them, especially good ones. And, nothing will ruin a weekend more rapidly than bleeding, throbbing feet. Plus, that gives you an opportunity to wear them around the house and yard for a while to get them thoroughly broken in.
After that, you can begin to look for your uniform.
As far as that goes, follow the advice you've already received...take it sllllllooooowwww and buy the good stuff!
If you spend the next year saving for a top-notch RD Type II shell jacket hand-made by the New Richmond Depot...do it!
If you have no idea what I'm talking about there, do a bit of research. I mean that with all due respect.
There are folks out there making very good reproductions of original gear. There are others who throw together "Confederate" jackets with modern wool (even calling it 100% wool when that claim is somewhat dubious).
Look into what unit your going to be portraying on a regular basis. Where were they located for the majority of the conflict? What depots were supplying their uniforms and equipment? These sorts of things will tell you exactly what kind of clothing you should be looking for, as well as who may be making what you need.
So, if you will be "in the field" as a Reb in the Army of Northern Virginia, you would want to try to begin with the aforementioned Richmond Depot Type II shell jacket and trousers in one of a couple of patterns. This is a good jumping off point since that style of uniform was issued for quite a while from the latter part of 1862 right on until the end. If your impression represents someone serving further west, look into the suppliers who made clothing for that theater of operations.
Basically, what I am saying is that you can't really go out and buy a "Confederate" uniform. (and that goes for the Yanks, as well)
A nice reference to get you started is posted here:
http://www.military-historians.org/company/journal/confederate/confederate-1.htm
It's not exactly a page-turner, but is full of very useful information.
Once you have your basic uniform put together, I'd say to go ahead and take the plunge into weaponry.
After that, the accoutrements such as a haversack, knapsack, groundcloths, and blankets would be next on the list.
Once you have yourself fairly well situated, you can go on and "specialize." There will always be that Peter Tait jacket or jeans cloth frock coat calling your name.
A couple of final, random, thoughts...
If you're on a budget, my best advice to you...learn to SEW! Sure, friends will laugh at you, but if you can eventually assemble a Charlie Childs jacket kit, the savings will more than make up for the torment. And, many items will not have the button holes hand sewn. The supplier will happily do it for you, for a fee. Instead, pocket the money and do it yourself.
Next, make sure you don't lose sight of the fact that you'll be starting out as a fresh fish. As such, your uniform should show it. Steer clear of hat cords and colored trim and other superfluous finery. These soldiers shunned anyone and anything that stood out from the rest. A man who tried to answer roll call dripping with brass buttons and gold braid would have been the butt of jokes for the remainder of his army career. So, keep things simple.
I am sure I've probably confused you more than I've helped, so please feel free to ask any questions you may have. I am in the midst of renovating a 150 year old house, so I am not around here very often, but I'll try to respond when I can.
Good luck!
Cheers and Fairwinds,
Brett Silver
Bringing the