Always be on the lookout for usable wood. You might be able to salvage some. You can use a metal detector to find nails and screws. You don’t need a full fledged metal detector. I use a pinpointer made by Garrett. If your wood has some woodboring beetles you can still use it if not eaten too badly. A healthy dose of cyfluthrin will take care of them.
While some people consider the circular saw to be more of a carpentry tool than a fine woodworking tool, but some would disagree. There may be no more versatile basic handheld power tool than a circular saw. When used with a clamp-on straight-edge, the circular saw can be just about as accurate as a table saw and handle quite a few of the tasks that one would attempt with a table saw, particularly cutting sheet goods such as plywood or medium-density fiberboard. When woodworking on a budget, a quality circular saw should be the first handheld power tool purchased, as it is the one that will likely be the most useful as you get started.
Own one junk chisel, probably about 1″. This will keep you from doing what you oughtn’t to your good chisels. It can be used and can be nearly trash. It’s going to hit caulk on masonry, junk stuck to the floor, interior cuts on thin sheets of aluminum, and other such abuse. If the back and bevel sort of intersect on an extra coarse stone, it’s sharp. I’ve sharpened mine on the concrete back stoop. (Not so great for the concrete)
I just moved overseas and had to give up all of my power tools due to space limitations and power incompatibility. Upon arrival the first power tool that I bought was a cordless drill/driver and the second was a circular saw. I then modified the saw to improve its performance for cabinet quality work by putting a zero clearance baseplate (just a piece of 1/4″ plywood screwed to the base) this allows the saw to cut plywood panels without tearing up the edges. I also bought a length of aluminum rectangle tube stock for a straight edge. Together the straight edge and the zero clearance baseplate makes the circular saw a fairly accurate tool for plywood construction projects. It’s not as easy to use as a Festool track saw but it cuts almost as clean and cost about 1/5th the price.
Block planes have become one of the most oft-used tools in a woodworker’s workshop. Some traditional woodworkers even keep them in their aprons! These little planes can be used to trim your joints, put chamfers on board edges, trim end grain, etc. I would recommend finding a low angle block plane, because the low angle lets you cut difficult grain more easily. My handplane buying guide goes into more detail about the features and brands that you should look for when purchasing a good quality block plane.
11-2. Pipe clamps, I have about 10 of them with varying lengths of black pipe in 1′ increments. I can switch out the clamps for larger lengths on larger projects, or downsize as needed. (very rarely do I need more than 6 clamps on a project during drying time, and when I do, it’s time for a cup of coffee and a 1/2 hour break while I wait) You keep your initial investment down, and buy them as you need them to increase your collection.
The fourth most important basic handheld power tool every beginner should buy is a random orbital sander. While palm sanders are less expensive and can use plain sandpaper (cut into one-fourth sections), the random orbital version uses hook-and-loop fastened sanding disks, and doesn't sand in patterns, using a random sanding motion instead. This motion will serve to reduce the chance that any sanding marks may appear on the stock due to the sanding. Of course, be certain that your local woodworking supplier has sanding disks readily available in a number of grits to fit the model that you choose, as the key to proper sanding is to use progressively finer grits as you sand to reduce or remove any marks that are left behind from the previous sanding.