My local Sam’s Club has this service, and it was the cheapest commercial one I could find a few years back for a few hundred slides I had from the 60s.
Their equipment may have been updated since I used the service, so if you look into it you might ask if any automatic correction is done and what the final resolution is in DPI. I just wanted to archive my slides before they completely rotted; for the occasional individual slide I pull up the jpeg from Sam’s and fix it myself.
I was satisfied, but this is obviously pretty low-end service at low-end cost. It was the cheapest place I could find. They did a decent job, I thought. Most of my slides ended up as jpegs in the 65-100 KByte range.