You forgot to mention that that is a 50 dollar (min) pack, with 5 bucks of HD shrink wrap, another 5 for a tube of goop, and that you need a 100 dollar charger (10 cell chargers arent cheap)and a 12 v power supply
25 bucks for an sla, 5 bucks for a float charger from harbor freight, is reasonably cost effective.