How to add Custom Items?

The spawn command to give the zipline would be givezipline zipline_default 2 and when you buy the zipline it takes your RP but dose not give you the item? Is there something im doing wrong? 

Hi! The Shop plugin runs these commands on behalf of the server, so the command must be a console/RCON command.

In your case, the correct command will look like this:

givezipline zipline_default 2 %steamid%

P.S. Original: givezipline    – give a zipline to a player (Suitable for RCON);

Okay, thank you!