How can I find Magazine On-Sale dates?!

How can I find Magazine On-Sale dates?

I agreed to help my niece do a major project for her college classes. Basically I just need to help her out with research, she's allowed helpers so it's not cheating.

She's doing a massive project that's about different media outlets. One of the things I need to do, is to find out On Sale dates for Magazines, and then try and find out when subscribers are getting thier magazines in thier mail boxes. I'm having luck with the second part of that, but no luck finding out Street, Shipping, or On Sale dates for magazines. I've got a list of about 300 magazines to hunt down dates for. I have tried contacting many of the publishers directly, but I've waited a couple weeks and gotten next to no replies back, so I'm starting to run out of time. She needs this phase of the data soon.

Does anyone know of any resources to find a more bulk listing of these types of statistics? Any help would be greatly appreciated.

8 months ago
Thanks for the help, but they are all monthly mags. I know some or maybe many magazines use a rotating schedule, meaning say the January Issue of a magazine goes on sale on December 5th, but then they use a 35 day cicle, so the Febuary Issue does go on sale until January 9th or around there. That is making my job more difficult.

most weekly magazines go on sale on THursdays