If you sell products to your customers, many of the items probably already have UPC barcodes you scan when ringing up sales. However, you can use barcodes on products or items for other purposes as ...
You can print a shipping label on eBay and send out items you've sold via standard USPS mail, or through FedEx and UPS.
To get started, open the Contacts app on your Mac and choosing New Group from the File menu, or by clicking on the + sign at the bottom and choosing New Group. Type a name for the group like Holidays ...