In my area some of the local camera shops do this, prices seem to range from 45 cents to $1.10 per slide. It's a common service at the small, old line camera shops- the ones that have been in business for 30+ years, love photography, and aren't franchises or parts of national chains.

I had a couple hundred done last year, output was approx. 2400 x 3400, 72 dpi .jpg, cost me less than 50 cents each.