What I most often leave is Amber. It is only ever worth 5 and it only stacks to 20.

Rubies and pearls are good. Rubies are worth 20 and stack to 20. Pearls stack to 50 but are found less often.

I'll even leave the coin behind and just sell the other stuff and put the gold in a box I leave at the trader by the portal. <gold is heavy to lug around>

What kind of prices for selling are you seeing?