2 things that stick out to me are: 1) too many steps to buy or sell something. If it was possible to make it one step (i.e. /shop sell dirt 20.0) it would be easier for folks to pick up. I know the sub categories make it difficult to do in one line and it may not be possible to make it one command instead of 2. 2) the help section doesn't explain it well. Washington explained it by giving an example for each command. (i.e. he said "to sell an item you type /shop sell item amount" "then you must type /shop select subcategorynumber" "that's the number left of the description". Not sure what the best way to phrase the /help for things, but it just made more since when he explained it.