BAM Question

I am looking at BAM what does it cost? And the AP license cost is that per year or a 1 time charge of 100.00? Will BAM limit the bandwidth at the SM level or at the head end. Meaning will they eat up my wireless bandwidth before they are sent through the BAM like a linux traffic shaper? Does the bam take in affect if the AP is set to 1x or 2x? If we set the user to 500K in the BAM and the AP is set to 2x enable will it compensate for that?