Is the T-Mobile 3G Data service too expensive for you? It’s $25 + 10 (unlimited text messaging) so I don’t think it’s much but if you rarely use the internet, try using $5.99 T-Mobile TZONES plan with your G1. Here are the settings for the phone after you subscribe:
Menu->Settings->Wireless Controls->Mobile Networks->Access Point Names->T-Mobile US
I input the following settings:
Name: T-Mobile US
APN: wap.voicestream.com
proxy: 216.155.165.050
port: 8080
Username: Not set
Password: Not set
Server: Not set
MMSC: unchanged from original (http://mms.msg.eng.t-mobile.com/mms/wapenc)
MMS Proxy: 216.155.165.050
MMS Port: 8080
MMC: unchanged (for me it was 310, I believe it is based on your location)
MNC: unchanged (for me it was 260, I believe it is based on your location)
APN type: Not set
As of now, this will not let you access GMAIL push, Google Maps, and access to the Android Market (use wifi hotspot). I’ll update if I find information around this dilemma.

