As [company]Sprint[/company] tinkers with its family plans to encourage prepaid customers to go postpaid, [company]T-Mobile[/company] is tweaking its entry-level prepaid plan. The barebones $40 Simple Starter plan is a good deal for light data users, but its 500MB cap means it wasn’t an option for many. On Monday, T-Mobile announced a $5 add-on which brings the LTE data cap up to a more reasonable 2GB. After that’s used up, your data gets shut off unless you buy a one-day 500MB bucket for $5 or a seven-day 1GB plan for $10. T-Mobile warns the plan is subject to change, and it will be available starting on September 3.