I'm planning on using my battery to run my
12 volt lights. I'll use a maintainer at campsite to charge
my battery. Would I be ok with marine batter or should I
pay a lot for an Optima battery?
If you don't take the time/effort to determine how much power you will use, it will be very difficult indeed to know how much power you need...
Something like saying that you are considering buying a new car, and asking how big an engine should I get?
If as you suggest, all your camping will be at a site with a 120 volt plugin to run your charger/maintainer, you may not even need a battery.
I'm not trying to be mean, or a smart A**, my point is that you are asking for an answer to a question that you have not yet defined to a point that anyone can give you an answer that will be of practical use.
Rob
Waiting for "someday" will leave you on your deathbed wondering why you didn't just rearrange your priorities and enjoy the time you had, instead of waiting for a "better" time to come along...