here, you have to get a permit to have a garage sale. when this was first brought about, the city said it was to combat a few persons that had been doing ongoing garage sales for weeks and months at a time. to fix this problem, the permit would be for three days, and would be a tool to be used to shut down the permanently run sales. the permit was free. it wasn't long before that "free" permit was $5.00. i think it's $10.00 now.
if a way to collect sales tax were to be figured out when you sell your buddy a wrench you never use anymore, or a tire and wheel that doesn't fit your current ride, they would be all over it !