I’ve had three brownouts this week, and this morning, Newegg sent me a promo featuring an APC Back-UPS BGE90M, a small 75-Watt UPS with three outlets and two USB charging ports for $25. These retail for $90 and frequently go on sale, but usually for closer to $40 or $50.
It’s intended for your router and modem and your phone, and its two-prong outlets discourage you from trying to use it to protect a modest computer from a brownout. I missed that detail when I ordered mine. I bought two.