Personally, I like Aircraft Tool Supply (
https://aircraft-tool.com) now that Avery is gone. Get a kit that doesn't include sockets, dogbones, and screwdrivers. I think either the Journeyman's or RV builder's kits would be good. Order (first!) a practice kit from Van's. You'll also want additional tools: bench grinder and drill press, compressor. Sockets, click-type torque wrench (in inch-pounds; the bigger ones you may want later for engine work), allen, phillps, slot drivers, and so on, can be sourced wherever you like. Mine are all Craftsman, others like Snap-on, but cheap will cost you in the long run. Other tools will occur to you as you build or are luxuries. I like a cut-off wheel and a band saw. A retiring A&P gave me a bending brake/shear. Extra cleco pliers (they are always on the other side of the project when you look for them - Murphy's Law Section 15.4.b). And storage. Lots of bins for small parts, shelves for big ones, cabinets for your tools, and rolling shelving (restaurant style) to have near your project. I also went to the nearby university and got an electronics workstation for my soldering gear and crimping tools plus a desk where I keep paperwork and a laptop with the plans. More recently, I got a filing cabinet to help store papers. I would also suggest getting the Vans Lightbox kit; it's more good practice and will dress up your shop space. Oh, and there are all the mundane things that we always forget: brooms, mops, degreaser, shop towels, fire extinguisher, and a good first aid kit.
Seem like a lot? You can start with the basics and add on as you progress. I built the tail kit of my RV-6A with little more than the Avery starter kit, Sears portable compressor, a hobby drill press, and tools I already had for working on cars. That was in '94. I set up my current hangar/shop in '15. So if it takes 20 years to accumulate, you'll understand there is no rush.
Oh, and clecos. Too many are never enough. My collection has quadrupled over the years (some are reserved only for fiberglass work).
