I'm sure the OP is looking for a simple setup, and is asking for a battery recommendation.
I would recommend starting out with an interstate rv/marine 12v, in the largest size to fit box, maybe group 27. It is best to get a fresh/close to current date battery, not one that has been sitting on a shelf for a year. Walmart sells a lot of batteries (mostly their brand), so usually fresh, with good charge.
In time, many lessons will be learned, and some of the more complicated, but good suggestions, will be an option for the OP.
