For those of you who sell online and take Paypal, check out their Multi-order shipping. Today was the first time I used it, and boy did it make things easier! When I sell on ebay it's usually 5-10 auctions at a time, and then I'd go thru and print labels and packing slips one at a time. With their Multi-order shipping you can print all the labels at one time. I figure it saved me somewhere between 10 and 20 minutes on the 6 lots I just packaged up. Assembly line instead of one of these and one of those... print, tape, repeat.
I still like to do them one at a time, I have ruined a couple labels while taping them on, and I like to complete the packaging before leaving the label page.
You can go back and reprint as long as the label hasn't been scanned by USPS. One reason I only list 5-10 at a time is I always dreaded sitting in front of the computer for an hour to get $40 in sales out.