Currently, T-Mobile requires you to sign up for the G1 Data Plan that cost $24.99. This includes the all you can use internet + 400 text messages (not a bad plan imo). However, my G1 is with a family plan that has the $20 text messaging plan for all lines. Thus, that 400 text message is worthless.

To save $5, you can sign up for the T-Mobile Total Internet Package, which is basically the same thing as the G1 Data plan without the 400 text messages.
How To Get This Plan Added:
1. Call T-Mobile and ask them to change your G1 Data Plan to the Total Internet Package.
2. Explain to them that you don’t need the 400 text messages in the G1 Data Plan as you already have a text messaging plan. They will alert you that you’re G1 will not work if you switch over. Let them know you’re willing to try it out and if it doesn’t, you’ll just call back.
Note: People have confirmed this alternative data plan does work with the G1. However, many have reported it will stop working after several days.
Why does this happen? It’s because T-Mobile has started to monitor phone via their assigned IMEI. As such, they know what phone you are using. My guess is that when a G1 is not signed up with the G1 data plan but the Total Internet Package, they put your phone number in a bucket where representatives will review, and later disconnect your data. The workaround solution is this. Have your SIM card in a non-G1 phone for about 2 weeks while you have this new Total Internet Package. This will hopefully, fool them into thinking you no longer have a G1 and remove you from the bucket. I haven’t tested this method but I plan to do this and will provide an update. It’s a lot of hassle for $5 and possibly not having access to data but in my case, I do not have a G1 as I sold mine and waiting for my backorder to arrive. Thus, I am going to try it anyways. Good Luck!
Update 11/8/2008:
They ended up removing my total internet data plan from my plan. Conclusion: It’s not worth the trouble saving $5.

