100 watt Solar decision

I'm afraid I don't know anyone with samsclub card. And I definitely will have to convert to LED lighting, thanks for the reminder. And I truely am interested in installing two 6volt golf cart batteries but am having the hardest time searching for one. I google things like "6 volt battery" or "6 volt golf cart battery" and it shows a few that are like 1,000$, a pack of 6 thats 80$ and a bunch of other weird things. Is there something at a certain website that would make it easier?

If i can get two 6 volts for under 200$ it would be worth it to me. But I am using these as the battery for my travel trailer, but I'm assuming that wouldn't matter, right? Specifically considering the emergency brake