Buying only what you need when you need it is good advice. This is especially true because of the variety of BB, FW, cassette, and crank designs.

I've bought lots of things from the LBS, but you can also find ANYTHING online. The prices plus shipping are calculated to be roughly competitive with store prices. The carriers, including USPS, are tripping over themselves to provide fast shipping, so don't pay premium shipping charges. If shipping is guaranteed within 10 business days, you'll probably have it within 5.

+1 on buying generic tools when possible. A sharp pair of standard wire cutters can cut cables effectively, and you will also have them for household repairs. There are specialty tools for opening and closing master links (two different tools!), but I've been able to do it with bare hands for closing and pliers for opening.

Buy decent files in two or three standard shapes - flat, round, triangular. They can help you de-burr threads on damaged fasteners, plus dozens of other general and bike-related jobs.

For the road, I carry a tire-lever set, a tube dusted with talc (forget patching by the side of the road), a mini-pump, and a 4" adjustable wrench. I modified the wrench by filing the jaws slightly wider to fit axle nuts on my older bikes.

I use the plastic-coated hanger hooks to hang bikes from my garage ceiling. I also have two screwed into my basement ceiling to suspend a bike from straps while working on it. The bike is stable enough to work on, and I don't need a pricey work stand.

My No. 1 Tool is the internet for how-to advice on doing things with or without tools. I love the video showing how to use your bike's chain to remove the freewheel. Talk about ingenuity!