How do you trade coins?

I assume you mean gold. It depends on what you're doing, for example if you wanted to sell another player an item directly you can send it with a CoD fee, and if you're selling pets you just set them to have a price.
For things that don't have inbuilt systems in the game, like art, you generally send a fairy mushroom with a CoD fee because they're really easy to get and not worth anything.

Whats a CoD

Cash on Deposit (or something like that)

Just click the item, (split stacks if u need to by shifting and clicking the item stack), then click the green arrow/envelope above the use item button, and put in the username and fee.

if i remember correctly it stands for Cash on Demand. (not 100% sure though)

Ok thanks!!!!

Thanks!!!!

I thought it was "Cash on Delivery". xD
(Technically, all of them work.)

(I don't remember, i htink ive seen both)