Both Walmart and Home Depot ARE retail stores. What did you mean to ask? Al

Not all mail order companies have retail outlets - Park Seeds is mail order only. If you want 'em, you gotta order online.

Or, if you don't like buying over the internet, Parks will still take your order on the phone, and even through the mail.;>)

Maybe it's the shipping issue ;)
I wanted to purchase 8 pkts of seed, but they wanted almost $4 to ship, and that's NOT going to happen!

I noticed that Burpee seeds are more expensive in the catalogue than they are in stores. I don't get it!

Compare the number of seeds in the packet. Oftentimes, the catalog packets have more seeds.

And make sure you're comparing apples to apples. Most of the seeds available in retail stores are the most common varieties. If you want something unusual you sometimes have to pay more.