If you got your inverter for $500.00, you have no room to complain about the cost of the other items, because you STOLE it! :agree:
I have the Model MS-2012, and I paid almost $1,500.00 for it on Amazon. I also have the Remote Panel for it, the Battery Monitor Kit, and the Mini Magnum Panel (for mounting and the circuit breaker panel), with plans to add the Automatic Generator Start Module (for my Honda EU3000i generator), and the PT-100 - Charge Controller (for Solar Panels). BTW, if you buy the Remote Panel, be careful which one you get, because one will work with the Generator Module and one won't. I bought the wrong one to start with and had to exchange it.
This all expensive equipment, but it's commercial grade and can be removed from the camper and reinstalled in a structure very easily for future use.