WTF won't do commercial recommendations, although personal experience is OK to talk about.
And I can't recommend inexpensive, because just like with cars, knives, and shoes, I'm a firm believer in "You get what you pay for. Even a single slot, GOOD watch winder will run you one or two hundred bucks. A couple Andrew Jacksons will get you a winder that will be loud enough to keep you awake at night, won't have variable speed control, won't be AC/DC powered, won't rotate clockwise AND counter-clockwise, will have a body that may fall apart in a year or two, and may have a motor that will burn out within a year. But then, you'll have the joy of shopping for ANOTHER winder!
Although I avoid recommendations, I WILL say this:
Before we switched owners, ORBITA was an Official Watch Talk Forum Sponsor. And I personally haven't seen or heard anyone badmouth WOLF, VOLTA, or RAPPORT.