All that is said above regarding the holiday cash is correct.
However, if you are leasing, some dealers are offering as an alternative that the $1,500 (+$750 loyalty) to be used as a credit towards the drive-off payment (Bank fee, DMV fee, tax on fees, 1st month payment, etc. and the cap cost reduction - if applicable).
Under such structure, the selling price is not reduced by $1,500 (+$750), but you can get the car with virtually no downpayment (or a very small one).
It's your decision to make. Do the lease math and see what fits your needs better.
Now: 2013 SG ZCP E92 M3; 2011 DSB X5d
Before: 2011 JZB E93 M3; 2008 Monaco Blue E90 328i; 2002 E46 Steel Blue 325i