Year before last, I had 2000+ slides to scan. I priced out various places (Walgreens, CVS, Online, etc...).
Based on the fact that all of these places required sending away of the slides as well as the price per slide and total cost, I ended up getting a scanner and doing it myself.
I picked up the Epson V700 which can scan slides, negatives, pictures and other items for around $500. The scanner does up to 12 35mm slides at a time and I believe 4 strips of 35mm strips. It would take about 2 hours to do 12 slides (that's with scanning and then the included software running to correct the pictures).
I couldn't be happier. Once you get the settings to your satisfaction, you put the slides/negatives in the attached frame, push a button and walk away. Come back in 2 hours and check to make sure it's all okay and then put another 12 on. I'd do this right as I got home from work and usually got 2 scans (24 slides) a day. Yeah it probably takes longer, but I KNOW the quality I'm getting and I KNOW they won't be lost in the mail.