there's a couple of good reasons to see a dealer for a new chain; the chainsaw chain sold in big-box stores is low-quality stuff with an outdated form of "safety" depth guages. This chain is difficult to sharpen, difficult to keep sharp, and is generally meant to prevent the store , the manufacturers, etc, from getting sued should you chop your arms and legs off. They assume that since the saw will be such a pain in the @ss to cut with, you'll seldom use it...
The dealer's shop is a fun place; he has all sorts of neat stuff there to drool over, like brand new high-quality chain saws, grass trimmers, you name it. A really high-quality dealer is quite happy to sell you a small part like a replacement chain for your little Mac, because it's his opportunity to become familiar with you and show you all the wonderful things he has at his store.
I take my wife shopping once in a while on the weekends...we hit a few stores, I sneak off to drool over the chain saws, skid-steers, and garden tractors, and then we have a sandwich and a coffee. If I couldn't go to the chainsaw store, i wouldn't go.