Hi Jordan
I've been a camera technician for years...started in 1989. I haven't repaired full time for 10 years, but I still repair the odd camera every now and then...I understand you are on a budget, so if I can suggest a few things...
file - buy a diamond file - these are small, flat files used to sharpen knives and fish hooks (mine came from a outdoors store) - this will be one of the handiest things in your kit...
screwdrivers...the cheap flat bladed ones you can buy for a couple of dollars are fine - buy 3 or 4 sets...now with your diamond file grind down the blades so that they are thinner, and actually fit into the slots on cameras. As you've bought a few sets you can also narrow the width of some of the blades so they fit better... I have a nice set of flat bladed screwdrivers, but I also have a dozen cheap screwdrivers that have given good service over 20 years...
You can also grind down the tips of the cross point screwdrivers to fit cameras better, but I would suggest buying a handle plus replacement tips (ebay is probably fine for these - the more tips you get ythe better) - just order a pack of each sized tip until you find the best size for you
Pliers - buy a few cheap pairs.
- Get at least one small needle nozed one (without serrations on the gripping part - if there are serrations then you need to grind them off as they will damage/mark things you grip)..
- a small flat nosed pair - good for bending right angles..flat blades - no serrations!
- a big pair - you would be surprised how often size matters...
Soldering iron - just about any soldering iron will do - I actually used to use a battery powered (rechargable) soldering iron when I only had a few joints to solder (like unsoldering flash contacts..). Get a small one with a stand (temp controlled is good, but not necessary if you are not planning on replacing IC's) - personally I use needle point tips - 1/32 and 1/64th..but then again I do IC's...
Lens removal tools.....
Rubber blocks - these are indespensible for taking name rings off lenses, removing counter screws etc. I would get a rubber stopped like the one off a chair, and fit a short piece or wooden dowell to it - this will let you unscrew caps from wind levers etc...
Larger rubber blocks will unscrew name rings etc - you can make them from rubber rollers (old fuser rollers from photocopiers are ideal) - just use a craft knife to cut them down to the right size - I have ones that are 49mm, 55mm and 67mm in diameter - I find these will remove 99% of name rings I come across..
You also need a tool to remove tight name rings/dismantle lenses etc...I have a couple..
- I bought a large pair of cheap needle nozed pliers, then ground the points down so they would fit into the slots around a retaining ring on a shutter. I can also dismantle lenses with these..If you get a second pair try to bend the points so they face outwards a little - you need this shape for some shutters, and it also helps prevent slippage when dismantling lenses..
- metal calipers - the spring loaded kind you use in toolmaking. In Australia you can buy them for $5 from a discount store..Get a couple of pairs - grind 1 pair to a point, and grind the other pair flat first, then taper the points (like flat screwdriver blades) - I've used these for 20 years, and because they are spring loaded and have a worm gear to set their width they are easier to hold...
Tweezers....don't skimp on them! I use 3 pairs - one is quite large and thick, with fine points - I use these for everything from undoing pin screws to holding springs, bending things etc...
Then get a needle nozed pair - these are iseal for hlding springs in shutters, holding wires when soldering etc..
And if you intend to work on shutters get a non-magnetic pair - last thing you want to do is to magnetise a part of a shutter (or aperture blades if you are cleaning oily diaphragm blades)...
Magnet - I have a old magnet off the back of a speaker - I magnetise the tips of some of my screwdrivers - much easier to work on a camera if the screw stays on the screwdriver tip (again don't use magnetic tools on shutters!)
Side cutters - for cutting wire (and cutting replacement screws down to size, springs etc...) - buy the best you can afford (I'd suggest 5 inch ones) - nothing worse than a blunt pair of cutters....
Ice cube tray - when I first started learing to repair I was taught to use a ice cube tray to keep groups of screws together - front cover, bottom cover, mirror box etc - it keeps oyu organised, and makes life eaiser...
Digital camera - drawing a wiring diagram is one thing, but having a photo is even better..you can use a film camera, but digital is immediate, and really this is the sort of job they are suited to..
If you are planning to repair Canon cameras a pair of small circlip pliers will come in handy too...
If you have any specific questions semd me a PM
Have fun!