If you have a knowledgeable friend who knows the difference between gems and dogs,there are real bargains out there on Craigs List.

Also, 64 miles/mo, mostly on short rides isn't a very demanding purpose. For this kind of light duty, you can do what the underclass does; buy a big box bike for $189.00, do basic maintenance as needed and chuck it if/when it needs anything major. Up here in Westchester, waiter, busboys and the like ride these 100+ miles a week and they typically last 2 years, which makes them solid value in cheap transportation, despite being sneered at as BSOs by bike snobs.