Why I hate brick and mortar stores

My SO and I were planning to tile our bathroom floor this holiday weekend. There's a cold joint in the concrete floor we're going to be tiling, so we need a crack isolation membrane to go under the tile. Through discussions on a message board we've discovered a highly recommended crack isolation membrane (Schluter Ditra), which we planned to purchase this weekend from one of the many local dealers the manufacturer listed on their website.

So, yesterday I called a number of the local dealers to see if they had the membrane in stock. Most stores either didn't have the membrane, didn't know what I was asking for, or stocked it in 100-foot rolls (we need about 10 feet). I finally found one store that sold the membrane by the foot, but it was closing shortly after I called so I couldn't pick it up until today. The Ditra membrane also requires a waterproofing strip (Schluter Kerdi-band) that covers the joints between the Ditra sheets, but the store that sold the Ditra didn't sell the Kerdi-band, so I had to continue calling around until I finally found a store that had a 100-foot roll of that in stock (nobody sold Kerdi-band by the foot).

Most of the stores closed by noon today, so I got up early and headed out to the two stores in the rain. The closest store on my outing sold only the Kerdi-band, and I was able to get that without incident. The second store was significantly further away; when I finally arrived, I had the following interaction with the young woman busily playing solitaire behind the desk:

Me: "Hi. I'd like to get 12 feet of the Schluter Ditra membrane."
Unhelpful clerk: "What company are you with?"
Me: "None."
Unhelpful clerk: "Are you a contractor?"
Me: "Nope. Just working on my bathroom."
Unhelpful clerk: "We don't sell to the public. You'll have to go somewhere else."
Me: "I only need 12 feet of this, and you're the only nearby store that sells it by the foot."
Unhelpful clerk: "We only sell to contractors and companies. You'll have to find someone who can buy it through us. Try calling a few places."
Me: Growl.

Nobody from this company had bothered to mention that they didn't sell to the public when I called them yesterday.

There was one other store in the area that sold the Ditra membrane by the foot (even further away, and more expensive), so I drove home and gave them a call to check that they still had it in stock (which they had confirmed yesterday) and get directions. Today, however, it was a different story. The employee I talked to said that they were out of stock, they didn't know when they'd be getting more stock in, and, to add insult to injury, they quoted me an even higher per-foot price than they'd given me yesterday. Oh yes, and they close at 3pm and won't be open until Monday.

A quick search online has found two stores (TileExperts and InstallerTools) and one eBay seller who are happy to sell Ditra by the foot to the public (and in rolls shorter than 100 feet). All the stores are quite conveniently open right now, tell me the exact price they're going to be charging, and will likely be more than happy to take my money. They're also cheaper than any of the local brick and mortar stores for the amount I need, including shipping.

I think I'll go place an order right now.