Marvel Comics have done it again. Over 300 collections of comics, some only just out in print, available digitally on ComiXology US and ComiXology UK on sale. There is a similar sale on ComiXology's owner Amazon, with slightly fewer titles available on the Kindle in the US — but not in the UK.
These come, and go. And mostly go. But if you are wanting to fill your boots, I would run, not walk.
Just ahead of the Diamond Retailer Summit in Chicago, man there are going to be some discussions about this kind of behaviour, I am sure, Especially with books only just released. And in previous weeks, often available at such prices on the day of release before the comic stores have even opened their doors.