I started commuting about 13.5 miles each way to work this spring, using a road bike I picked up 20 years ago used.
I picked up a used Trek road bike off Craigslist for something a little lighter and more current. Didn't get the deal I thought I did, as I had to buy new chainrings, chain & cassette.
Still commuting, now that it's cold here -- 23F when I left this morning. I feel so much better on the days I ride in.