You can wire into harness of the towing vehicle (best I remember its the BLUE WIRE) to the harness of trailer to pickup 12 volts deciated for items like that. If you want a battery on the trailer you need to wire in an isolater so the battery in trailer will charge even if the tow vehicle batter has stopped charging. The inverter can be picked up from almost any automotive store or even a truck stop. Think the average price for a 300 watt inverter is around $39.00 or so. If you have a R/V repair shop close ask there for help.