Question about data plan

[Sonic1213]

Yes, should I use something else?
Please let me know. Thx

[techierob]

Nope using wifi is how it's done.
Try emailing it to yourself. Apple still hasn't done a fix on profiles. (through web links) IPCC hacks have been fixed or broken actually.
I'm running 4.0 and it still works fine. In your profile put down the version of Iphone you have and iOS running that will help greatly.

Also there are a few sites that do Profile APNs have you tried another site?

[Sonic1213]

I am running 4.0.1 on a 3G. After I email it to myself what do I have to do with it? Please let me know.

[techierob]

Open your email with your iphone and try the install.

Here is an article with your exact problem.
Update #3: Safari could not install a profile due to an unknown error. | iPhone APN Changer

[Sonic1213]

It worked like a charm, thank you

[techierob]

It worked like a charm, thank you

Let us know how long it takes for them to catch you on the cheap plan. (If at all)