I recently bought a used Droid 1 on ebay for cheap. Switched from Verizon to Page Plus (prepaid and no data plan) and am saving buckets of money compared to my dumbphone plan and since I'm always in WiFi for 90% of the time I get to have all the perks of a smartphone. Easy e-mail checks in meetings, apps for scouring forums,web browsing on the go to check movie times or what have you, etc.
My droid has replaced my GPS (maps downloaded to SD, don't need data plan for this) and my expensive MP3 playing alarm clock (Droid in a media dock = success). Smartphones don't have to be expensive, the Droid 1 is plenty fast. Faster if rooted and overclocked. If you got good wifi coverage then you don't need an expensive data plan. After flipping the dumbphone, GPS and alarm clock on ebay, I made money on the switch.