Hmm. "Bare minimum" and "functioning." That could mean a lot of things. I'll assume you've got some money.

I disagree with ratchets and pedal wrenches being essential. You can use a 30.-something (big fat) seatpost that's bent as a small dummy bar. We also have a salvaged length of steel pipe about four feet long that fits over most any wrench or tool. This provides excellent leverage and has saved my ass many times.

A workstand. No way around it really. We found a used double Park stand.
-- 1 large adjustable wrench.
-- A set of metric wrenches. 6-19mm is nice, but 8-15mm is absolutely essential. You'll probably want doubles on the 13, 14, and 15. You can get crap Chinese ones for a while, but the box end will round out really quickly. Sturdy pricey American-made ones are worth it for longevity.
-- Spoke wrench. Also, truing stands are pricey but wheels are trouble enough without one.
-- Cone wrenches. We lived with the double-ended Park ones for a year and a half, but the blue-handled ones are excellent (quality and leverage-wise). A set of 13mm through 17 or 18mm will do it.
-- A caliper wrench, for brakes. It's a Park wrench with open-ended 8mm and 10mm. Old brakes are really touchy on the spring tension and if you don't lock the adjustment, the brakes will work themselves loose and fall off. Not safe.
-- Set of hex keys. You can get any old metric set. The Park set comes in a sheath and has every size I've ever used on a bike. The long end has a diamondy-shaped head so you can use it at an angle in tight clearance. We've had these for two years and never lost or broken one.
-- Crank extractor. Not the Isis drive one. Regular ol' puller. There's a double-sided socket wrench (14mm and 15mm) for removing and reinstalling the nuts (absolutely crucial). For cotter cranks, you can improvise a punch with an old pedal axle.
-- Ball peen hammer.
-- Lockring tool. There's an adjustable crap one, and there's a fucking sweet one with a chainwhip on the other end that is a pleasure to use. Also for bottom brackets -- a pin spanner, but you can get away with an improvised awl and hammer (expect this method to fuck up a lot of BBs, though).
-- Chain tool. I'd say start with a couple of the "mini brute" with extra pins, but you can also file the smushed-down pins back into round.  What I like about the mini brute is it has a section for spreading the bushings to remove stiff links.
-- Some metal files from a pawnshop are cheap and great for all kinds of things, especially for cleaning up rusty threads.
-- Cable cutters.
-- Pliers. Another pawn shop endeavor.
-- Air pump(s). Rebuildable ones are great. We find the life of a high-usage pump is greatly extended by using a presta valve adapter, which are a few cents apiece in bulk.
-- Tire levers. Crucial. Metal ones last longer but don't slide on the rim as well as plastic.

Also, a vice is also very, very handy for a lot of things, like getting the pedal off a rounded crank. We've got a bench mount one. I can't imagine overhauling or adjusting a hub without an axle vice.

You'll also need chemicals.

-- Grease. We use tubs of red grease from the auto store. It's cheap and light enough for bearings that don't run hot (as in bikes). Stay away from the real stiff grease.
-- Chain lube. So far we're running on donations on this. I like the Syn Lube a lot. I hate White Lightning because it makes a noisy chain. Pedro's Ice Wax has been very good to me. We have a gallon and are pleased.
-- Penetrating oil. Tri-Flo is expensive but the best I've used, so throw this on squeaky derailleur pulleys and two-drops-will-do stuff. Liquid Wrench is a good cheap one for letting set on stuck seatposts and corroded threads and the like.
-- Degreaser. We get the orange citrus stuff by the gallon from the dollar store. A spray bottle of it is great.

I also use a lot of steel wool. A bag of medium and a bag of superfine covers the bases pretty well. Wire brushes are also excellent to have. Ah, and sandpaper for cable rehab.

That's all I can think of off the top of my head. I'm headed in to the ol' Bike City now, so I'll keep an eye on what else I can't function without.

I'd love to help on the Wiki, by the way.


--andrea
Bike City Recyclery, Fayetteville, AR