fi you can get Odd tools for a good price but buying for the sake of adding to your collection is not the most cost effective way, IMO,
I usually wait until I have a need, and then buy, for example I may buy a kit, say a kit of special sockets, or kit of torx, some times I buy only what I need, but start with your basics, 1/4", 3/8", 1/2" sockets, and two sets of box and open end wrench's, that basically cover your socket sizes,
depending on what one has one may only need metric now, but would think having SAE would be good as well, the thing about special tools is most of the time there limited to one brand or model, and the next years is some thing different,
adding U joint sockets, impact sockets, impact wrench, ( probably would not get a 3/4 or 1 inch drive sockets unless you have need for them, I would suggest 1/2 impact wrench first, and then a 3/8" and or a 3/8 ratchet wrench,
short wrenches, thin or tappet wrenches, ( I find various extensions, and socket adaptors, 1/2 to 3/8 and 3/8 to 1/4 ect, can be very handy),
I even have a set of 8 point sockets for square nuts, (not that many used any more but on pre 1960 machinery they can come in handy),
VOM meter, inductive ammeter for checking out put of alternators or the draw of starter, (some companies makes a small unit one lays over the wire), battery load tester,
