Are you talking about Estimated Taxes? Check the IRS website for this: http://www.irs.gov/Businesses/Small-Businesses-&-Self-Employed/ When you use some online services to pay your IRS tax with a credit card, a fee of 1.87% to 2.35% of the payment amount will be added to your bill. You may make a profit by using AMEX gift cards. It seems doable.