Most owner-builders buy their tools at flea markets, junk shops, garage sales, barn sales, want ads in local papers, etc.
IMPORTANT: They buy their building materials in the same way — from salvage dealers, Little Nickel ads, BUY-SELL ads, country auctions, demolition companies, etc., etc. In this way, they are often able to build their homes for a FRACTION of what it costs the ‘non-thinkers.’
Under some circumstances, it can take a lot of time to accumulate the tools and material in the cheapest way. Consequently, it is advantageous to learn about this stuff immediately — so you will have time to shop appropriately and buy at the lowest cost.