It's a good one but I can see a pitfall:
You might buy something that you find is unsellable, killing momentum.
A friend of mine - Joyce - had a good idea and put it in to practice, it was called jam-trading.
In the Netherlands the traffic jams are terrible and people end up next to each other, often for long times.
So she devised this game (not without danger to passing motorcycles), take anything from your car and try to trade it with the people next to you for something that you value more.
When the cars move again you get parked next to your 'next victim', rinse & repeat.
They started out with a fairly squishy apple (the food kind, not the digital kind), and managed to trade it all the way up to a notebook and a pretty neat pen over a stretch of about 5 kilometers.
A 1:20 fold increase in value or so.
Not bad for a simple idea...