Buy an item on behalf of your end-user.
ORDER_CREATED: Order created successfullyAUTH_MISSING: No API key providedINVALID_KEY: Invalid API keyBAD_REQUEST_ERROR: Invalid request parametersSTORE_NOT_FOUND: Store ID not foundUSER_NOT_FOUND: User ID not foundSTORE_NOT_VERIFIED: Store is not verified yetFORBIDDEN: Not authorized to access storeINTERNAL_ERROR: Server error occurred