T-Mobile has just announced a new type of no-contract phone plan that falls under its prepaid service options. But this one is even more flexible than a month-to-month plan: Customers can pay as little as $1 a day, for days that they use the phone.

This type of plan appears designed for infrequent cell-phone users; more frequent users may want to do the math first. Day-to-day may be more flexible, but daily charges could add up to a monthly cost of approximately $30 to $90 a month, depending on which of the following plans you choose:

Pay by the day:

• $1 a day includes unlimited text, and phone calls cost 10 cents a minute.
  
• $2 a day covers unlimited talk and text, and unlimited Web access at 2G speed.
  
• $3 a day gets you both unlimited talk and text plus unlimited Web access up to the first 200MB per day, at up to 4G speed.

For more details you can check out T-Mobile's prepaid pay-by-the-day plan listings. Keep in mind, however that our latest Ratings of wireless carriers (available to subscribers) show that T-Mobile service isn't the most highly regarded by the thousands of consumers who responded to our annual survey.

For cell phone subscribers who don't opt for pay-by-day plans, wireless carriers have recently said they will provide free alerts to customers when they are close to exceeding their plan limits in voice, text, and data. Consumers Union, the public policy and advocacy division of Consumer Reports, will work with the FCC on a website to track industry compliance with the just-announced Code of Conduct for wireless carriers. To avoid bill shock however, and save money on your wireless phone service, see Best cell-phone plans and providers and check out our tips for avoiding overage charges.

T-Mobile offers pay-per-day plan [CNet]