I've purchased items that were "on sale" from Musicians Friend and Guitar Center previously.
I tried to buy a new Ashdown amp that seemed like a really good deal though Musicians Friend. The product said it was in stock, but they called me to say it had been discontinued. I contacted Ashdown and Mark Gooday responded to me saying that the item was indeed not discontinued. So it seems they just weren't honoring their sale prices.
I tried to order another item on sale from guitar center. A DigiTech cabdryVR cab simulator. It was priced about 75 percent off usual price, and I ordered it online because it said it was in stock. My order was cancelled without any contact from guitar center. The sale was still going on at that point, and the item still said in stock, so I ordered it again and the order was cancelled again.
At this point I don't trust either company to honor their sales prices, and I only ever buy from the guitar center used section, and only if I find something priced well below market value. Even then I expect to potentially return things because of undisclosed damage or general misrepresentation of the product.
They have pretty crappy business practices, but sometimes one of their uniformed employees buys an instrument from an uniformed customer and if you catch the online posting early enough you can get a guitar worth $1000 for only $400.