If you are going over your cell phone minutes for the month, call your provider and tell them you want to switch to a plan with more minutes for the current month. With T-Mobile, you have to call them on the telephone, you can’t just use their web site to change your plan.
Likewise, if you are using less minutes, switch to a less expensive plan for the current month. I’ve done this several times now with T-Mobile. Before moving, I had a 300 minute plan. When I was driving cross-country, I upped to the 1,000 minute plan. Now I’m back down to 600 minutes.
Getting hit with overages of $0.40/minute is st00pid.
In a few months, after I settle down with a lease on November 15th, I might join in with my sister’s plan, getting 1,000 minutes for $30/month. I’ll wait to see how good T-Mobile service is in my new house.