Buy low at garage sales, sell high on Amazon
Garage Sales — You can get real lucky and find yourself a collectible comic book for a quarter. I’ve found a ton of computers, monitors, but mainly printers. The great thing about garage sales is that they’re basically expecting to be low-balled, whereas on Craigslist some people WILL get offended. The most I pay for a printer is $10 there, any more I just walk away because it’s not worth it unless you know it’s a $200 printer. Most of the time you can buy the printer for $10, and sell it for $30, but that’s not what we’re looking for, we’re looking for that 10X baby. We’re trying to buy a printer for $10, sell it for +$100. You want to steer clear of items that aren’t the complete package, meaning that if you buy a printer, and it doesn’t have the printer cable, it’s not going to be worth it.
HP for instance has proprietary power cords, (Like this one) meaning they aren’t standard and are specific to each printer. So if you buy a printer for $10, and you have to go out and buy the power cord for $10, and you end up selling it for $30, your profit will likely be eaten up by the Amazon shipping credit difference issue. But you want to test these items out, as best as you can on the go, BTW this goes for Craigslist too. What I used to do was bring a laptop, and some spare power, USB, VGA cords in my car.
Curb alerts are different, you have to see the ad, and show up in time for someone to not have beat you to it. These are tough, especially if its high-end and it’s not real close to you, but impossible. I’ve seen a curb alert for a computer keyboard and monitor about 2 hours late, I drove 15 mins and it was still there. Sometimes you have to just take the risk, downside is gas and time wasted, upside is profit.