When they were sent through the mail, I received them regularly. Once they went to email, I rarely, if ever, get one.
I always have many items in my Wish List that are over $50.00 so they would never go to waste, but sadly I must be off the list for some reason. I hear they are sent at random, but I'm not sure I believe it. If they were indeed random, then I'd get them every now and then, but now they've screeched to a halt completely and I don't know why. It's certainly not because I don't spend enough with QVC, because I believe I singlehandedly keep them in business! 
"Summer afternoon-summer afternoon; to me those have always been the two most beautiful words in the English language." ~Henry James