I don't use UPS's for their surge protectors for the same reason I don't spend any money on plugin surge protectors. I don't pay any attention to their surge ratings.
If you want a UPS, buy one that meets your need and fits your budget. Your needs should factor in the likelihood of power outages in your area, the runtime you need, and how many devices you need powered. There are calculators on the APC and other web sites that can be used to determine runtime. These are helpful to determine how big or small a UPS meets your needs and budget.
And yes, replacement batteries prices can be almost the cost of a new UPS. Sometimes you can find new UPSs on sale for less than replacement batteries. And there are off-brand batteries available at lower prices. It's sorta like buying ink-jet printer ink. But don't let that stop you from getting a UPS if you decide you need one. Just know that in a few years, a replacement battery or UPS should be in the budget.