I have 1GB data each month (for an outrageous price ), and I've only used 30MB so far, since I got my phone a week ago - but I've been at home the last week, so I've been using my wifi.

If you have access to wifi most of the time, 500MB should be more than enough, I believe.

Toja, how much do you pay? Internet is quite cheap in Sweden, isn't it?