Feature addition and cancellation

Hi, I just purchased a BM phone under the Share 20 plan w/Fab 5. I was wondering if I add Mobile Browser (unlimited) through bell.ca for $10/m as a feature and cancel it in the next month, is there any penalty? Can I just do this on and off throughout the contract, like say if one month I want some games and ringtones etc.?

Thanks for you help,
Nate

When I was last in the Bell Mobility store changing my plans (last week), the Bell rep told me that I could change my plan features up to 3x per year.