Go with the more inexpensive version. Get a 12v 7amp gell cell and place your starter on top of it. Get a couple of large, really large zip ties and zip tie the battery to the starter. Then just simply connect the starter's leads to the batteries. There you go,,,easy, very dependable, inexpensive and will last about a month or even more before you need to recharge it.

I'm on my laptop now, but if you need a pic of my setup let me know. I have a pics of it on my desk top.

take care