Crown battery in Twinsburg had a marine battery for $100 that should suit the purpose. I had been there once before but this time after following a detour on Highland road they were no longer in same location. Glad I had a my cell phone, a quick call to the headquarters and they were able to direct me to the new location a few doors down.
Unless you have a very small solar panel you can't just hot wire it in to the battery, you need a regulator. The regulator matches the output of the solar panel to the battery's requirements preventing overcharge and back-flow.
Here it is hooked to the battery only. The lights on the left show solar power present, bulk charge mode, and the battery charge level (bottom 4 leds)
The top switch is for gel cells or lead acid. I have the lead acid type which requires water to be added periodically. The other switch changes the display from voltage (shown) to amperage or power flow.