Extra Pay Check

For those of you who get paid every other week and will be getting 3 checks this month, what are your plans for that "extra" money?

I have 2 options, either

1. Complete car repairs ($700) and put the rest toward paying off Master Card

or

2. Pay off Master Card and charge some of the repairs on Amex and/or Visa.

That way I can have a zero balance on one card (to motivate me and perhaps raise credit score), and I can pay off the charge with my tax refund.

I know the smart thing is to use the cash to repair the car since I don't plan on buying a new one any time soon, but I would get a lot of satisfaction out of seeing a card with a zero balance.

What do you think?