neb: Speaking of Aliexpress, does anyone know anything useful you can do with their coins? Various online forums indicate that they're completely useless in practice (e.g. you can spend a pile of coins to get ten cents off something that you could otherwise get $5 off by buying from the different vendor), and personal experience is also that they're useless, but I thought I'd ask in case anyone has figured out what you can do with them.

I think they are only an incentive to get people to visit the site every day, but they otherwise offer very little benefit. Visiting daily used to count towards your rating and a higher rating is useful for getting quicker handling of disputes. Not sure if that's still the case, but if you're there you might as well click to get coins.

My advice is to shop as you normally would and if you happen to get a few cents off at checkout, be grateful.