It depends on which tax credit you are talking about. Some states apparently have tax credits or other incentives for purchasing a Prius. The federal Tax credit form 8834 specifically dis-qualifies the Toyota Prius and Honda Insight on the 2001 federal return, although I believe some have taken the entire approx. 2,000 dollar credit anyway on their 2000 or 2001 return, hoping that they don't get audited. This was not a fixed 2000 but 10% of the cost of the car up to 4,000 dollars. Example: If you paid 20,486 for the car, then you could theoretically get back 2,048.60. There were some other hitches to the form 8834 credit. Other forms were required including the Alternative Minimum Tax calculation (AMT) which threw another wrinkle into it. The other federal tax deal is the Clean Fuel deduction which goes on line 32 where its is deducted from the adjusted Gross income. This deduction has recently been certified as a legitimate deduction and it's 2.000 dollars, so basically if you are in the 15% bracket you will actually get about 300 dollars, or if in the 28% bracket 560 dollars, etc, etc.