Backup Solutions for Sump Pumps

I like posting things like this on FR as there is a lot of wisdom from members. I have a fairly new 1/3 hp Zoeller sump pump but considering a backup in case of power outage: 1. Whole house generator connected to natural gas. Depending on model, kW, this can cost $10-25,000. 2. Traditional generator that plugs into utility meter socket or a smaller standalone just for the pump. $500 - $3,000 solution. 3. UPS with two batteries but fairly expensive. $3,000 by my estimation. Allows for software monitoring of system. 4. Two battery system with inverter, charger, inline fuse...