For a more low-tech approach, consider giving yourself a fixed cash allowance for discretionary expenses like food and shopping.

FORBES: 4 Steps to Deal with Your Own Debt Ceiling

Notice 2012-72 contains the standard mileage rates, the amount a taxpayer must use in calculating reductions to basis for depreciation taken under the business standard mileage rate, and the maximum standard automobile cost that a taxpayer may use in computing the allowance under a fixed and variable rate plan.

FORBES: 2013 IRS Mileage Rate Increases To 56.5 Cents Per Mile

Customers signing up to You Fix will get a set allowance of minutes, texts and a Flexible Booster for a fixed monthly amount, on a short 12 month plan.

ENGADGET: T-Mobile's You Fix gives budget-minded Brits a new approach to pay-as-you-go