For me shopping locally is the only way to go.
I tend to do a good bit of that as well. I love hitting yard sales for chainsaws and weed eaters that I can get dirt cheap (Paid $2.00 for a Craftsman Brushwhacker, $5 in a primer bulb and 6" of new hose and it was running and ready to turn), usually $5-10 per unit.
But, where you really find some of the good stuff for our business is estate sales. I've picked up boxes of new spark plugs, many quarts of 2 stroke oil, spools of weed whacker cord, lawn mower blades, pretty much everything at estate sales for virtually pennies on the dollar. A different type of people generally go to estate sales than yard sales. Estaters tend to be the collectors of the group and they aren't really looking too much at what's in the garage area or out in the tool shed.
A LOT of my hand tools like nut drivers have all been picked up at yard sales for as little as .25 to .50 cents each.. Even scored a Craftsman 18v Evolv drill driver with battery and charger this past weekend for $3.00. Had to attached the charging cable to the base because someone had cut it but, it charges and works great.
For those cables, that's definitely one thing I'll grab off a mower before I have to totally scrap it.. The handlebars are another keeper if they're in great condition. Sometimes you can reuse the motor, other times it's just the deck but, a lot of them are universal.. Ohh, and I always take the blade off the motors if the motor is destined for the scrapper. My wire wheel on my bench grinder cleans them up, then a good sharpening and a coat of Rust O'leum paint (.50 a can at yard sales) helps keep them from rusting a bit more.
Still trying to decide what I want to put in my step van but, it's getting closer.. Gotta stop and answer phone calls, fix stuff, and sell stuff all the time..