The cost to e-file varies depending on which tax preparation software or online tax preparation site you are using. If you are participating in the IRS' Free File program using one of the free tax software programs made available by the participating partners, there is no cost. If you purchase tax preparation software such as H&R Block's TaxCut or Intuit's TurboTax, you can expect to pay in the $20 to $30 range to e-file. If you need to file a state return, you'll probably have to pay more for that. However, you may be able to get all or part of the e-file fee refunded, since some software manufacturers offer rebates as incentives. Online tax preparation sites may offer free or low-cost tax preparation tools but then charge more to actually e-file. Shop around to make sure you're getting the best tools, support, and service for your money!