Newspaper articles is awesome, but most of the places require you to go somewhere to view the microfiche. I haven't really looked into it here locally. I need to call the Newspaper, and ask them what their policy is.
One thing about looking through actual newspapers... the sales scans would be invaluable. Ads from Toys R Us and Kay Bee toys and stuff like that. Some of them would be wildly inaccurate, but again, the more information that could weigh in on it, the merrier.
Also, have you guys seen that one video on YouTube where somebody actually is walking through a Toys R Us aisle, filming the price tags of Genesis games ? It was the Arden way Toys R Us in Sacramento, CA, a place I've been to plenty of times. (Unfortunately, I was in San Diego at the time of the TG-16 and went to a Toys R Us in the San Diego area to get my games and stuff. Bought my TG-16 system at Montgomery Wards.
Seeing that video, does definitely bring back memories.