I print mine out and mail them in. Why should I pay an additional fee to e-file just to make things easier and cheaper for the IRS?
I used TurboTax to prepare my returns. Like someone else said, I can deduct the cost of the software. Since I made more than $50,000 it would've cost me $15 to e-file my federal return and another $15 to e-file my Missouri return. That's $30 to e-file both returns. It was a lot cheaper to mail them in. When the IRS starts making e-filing free (or at least cheaper than mailing my returns in), I'll mail them in. If it matters, I was due a refund on both returns.
Yes, TurboTax offers a rebate for the cost of e-filing one federal return, but you have to mail in the rebate form. So, if I have to mail something anyway, why not just mail the tax return to begin with? Then, I don't have to wait 6-8 weeks for them to send me my $15 e-filing fee back.