So, I have to admit, this was back when I was a (apparently clueless) teenager, and basically what I was amounted to being a gopher and extra set of hands. It never occurred to me that the guys owned their own tools, I didn't see them hauling them in/out.
The guys I know now, I know through the owner of a rather large auto shop. He is frequently talking about expensive stuff he's bought for the shop, so I've just assumed he bought everything.
Side note - back in the day, it was pretty obvious I wasn't particularly well-suited to that sort of work. I always envied (still do, actually) of guys who know cars inside and out.