Depending on how your shipper does it, it can be cheaper to pick it up at the local store. I say this because if I am shipping a package that is "Hold for Pickup", I tend to ship it Standard Overnight, instead of Priority Overnight (I use FedEx). The box will arrive at the store at the same time no matter which you use (normally by 6:30 am). The Priority cost increase is because if it is delivery, it has to be delivered by 10:30, where the Standard doesn't have to be delivered until 4:00. Some people don't trust that method, and would prefer to pay the extra $5-$8 for the Priority service.
Just my .02,