My 2 cents: don't cheap out on either. Get yourself a nice Minnkota or similar. I'm guessing that size boat you'd want a 50lb thrust or more. A used one would be totally fine, save yourself a few bucks. For the battery don't cheap out, I'd buy a brand new quality deep cycle. Yes they are pricey but you get what you pay for. IMO the Costco Kirkland batteries are garbage. They are rebranded Interstate. I'd pay a bit more for am East Penn group 27 size from Napa. They battery will say "Napa" on it but they are East Penn. Super good batteries! My last deep cycle I got 7 years out of it, even then it was still "fine" it just didn't hold a charge as well, so I replaced it. Lastly get a good charger and don't fast charge it. I charge mine an 2A which is what the guy at NAPA recommended.