A few months back, I got a Voq Professional phone. This was an ill-fated (pdf file) attempt by Sierra Wireless to enter the smartphone market. Basically, it is a GSM Windows Smartphone 2003 phone with an interesting foldout keyboard. Being the frugal guy that I am, I decided to give the phone a shot since it sounded interesting and they were trying to unload all the inventory cheap.
Despite some shortcomings (no Bluetooth or camera), I like this phone. It does everything I want and was around $100 on eBay. I purchased the stereo headset and a 1gb SD card for about $30 so I can listen to music and a pretty decent clip case that stays on my belt for about $10 (the case is nice - stays on even while running). So, with all of the accessories, I was out about $150.
I signed up for T-Mobile withT-MobileWeb (web and POP access) for about $40 per month (tax inclusive) and configured the phone to connect to the Internet. The only drawbacks I have seen so far is that the web isn't very fast over GPRS and that email is a bit fiddly (sometimes you have to re-enter your password event though you click the save password option). Beside that, everything works as well as I would hope. So, if you are in the market for low-cost voice, email and Web and you don't mind hacking on a few settings, the Voq/T-Mobile combo is worth considering.