Most recently, the laptop order from Dell was delayed by over 2 weeks due to order volume and some people reported that when they called to bitch they were offered anywhere from $25 to $100 dollars. There seems to be no rhymme or reason to it other than which customer service rep you happen to get and whether they're in the mood to give away money.
The efforts I've made to get such things in the past have never actually panned out till today. I dunno if most of you will remember, but the Wii's I bought so long ago on Black Friday said in their description they were supposed to come with Wii Play and an extra Numchuk. Amazon did a whole tapdance that started with outright lies and ended with it was a mistake. I decided to try a chargeback on my Visa in the amount of the missing components and after mailing in supporting documents and months of miscommunications and mixups, some customer service guy credited me with $209.94 today. Spiffyness.