I regularly see tiny trucks carrying oversized (and precarious) stacks of what appear to be discarded, or perhaps stolen, pallets hither and yon. Is this legal? It looks extremely unsafe. And what are they for? Can one sell them somewhere? —Renae N.
I wouldn't worry about it, Renae—I regularly see tiny men with oversized marching-band instruments parading across my bedroom ceiling, and they've never dropped one. (Sometimes I wonder why people think I would be a good person to ask about whether things are "safe" or "legal.")
That said, assuming the driver has taken reasonable precautions, those piles of pallets are perfectly lawful: Oregon law allows loads up to 14 feet high and 8½ feet wide. (In what may have been a legislative oversight, no comparable provision is made for how small the vehicle carrying such a load may be, leading to the vehicle/cargo mismatch you find so jarring.)
Federal cargo regulations also require such loads to be tightly stacked and secured with at east two lateral tie-downs. There's very little hard data on how safe these stacks really are, but the fact that so far no one has posted a YouTube video of one collapsing seems like a pretty good sign.
And, to be fair, the operator has a vested interest in his charges arriving safely as their destination: As you surmise, used pallets can bring anywhere from one to five bucks with the right buyer, according to the Oregon Pallet Recycling Exchange, a sort of Match.com for pallets and their admirers.
Collecting that cash should be but a simple matter of moving the goods from their source to the place where they are desired. Of course, nothing is as easy as it sounds. Still, numerous side-hustle-promoting websites claim one can make $100 to $150 a day for this work.
That's enough to provide a (paperwork-free) living for a hard-working individual—even it's not, apparently, the kind of money that would let a person buy themselves a full-sized truck in good condition.