Grab an AGM type battery from Advanced auto parts. They'll run about $100, but there is almost always a 40% off $100 coupon you can use(TRT41 is a current one). An AGM battery should be able to last longer than your standard lead-acid battery, so the extra price is usually worth it. If the one you want is below $100, throw in a couple filler items like spark plugs. Buy online and pick up in store to save on shipping.