I usually update incentive information once a month, early in the month. Which is generally often enough, as most manufacturers update incentives on a monthly basis.

But in the latter half of last month GM added $500 to $1,250 of “bonus cash” to some of its models. This money is in addition to the regular rebates, and unlike the regular rebates can be used in combination with low-rate GMAC financing.

And, for the first half of February, they’ve taken some or all of the bonus cash away from these models and put it on a new set.

What’s the point of having some incentives (at least potentially) end mid-month? Perhaps to pull some people who usually wait until the end of the month to buy a car to buy one mid-month instead.

So, for GM at least, I’m going to have to update incentive information twice a month.

Lesson for you: no bonus cash on the GM model you want? Wait a couple of weeks.