Call them up, ask for possible charges for:
-proofing/sample
-corrections
Find out if their "Free Shipping" is to the distributor (this would be you or UMD) or to the individual recipients. In the case that you will be distributor, you may need to calculate a 'base' shipping fee for everyone else. $5 is pretty reasonable if that's the case, if it's only a jersey.
Sales tax is 8.25% or so.