You could make a post in the BST for one. Do you have an idea of what model you'd like to try? If you want "the first Gillettes" be prepared to pay a large amount they're going for 100's, where as a razor from the WW1 era is drastically less expensive. You should check out Achims site and poke around his collection and maybe you'll find something that catches your eye. http://www.mr-razor.com/
After the early Single Rings and Double Rings, the Old Type came out and was made though WWI and through most of the 20's I think. In the early 20's the New Improved came out in various configurations and finishes and then just the New came out. After that you got into the first 1 piece TTO's that were OC mid 30's roughly, then TTO with safety bar, late 30's or early 40's, not 100% sure. Then Adjustables in the 50's, 60's and 70's. Then the demise of the entire DE razor in the 80's.
I may be off by a couple of years in places, but that should be a general layout of what and when. There are a ton of vintage Gillette's that can be had for well under $100, the majority of those under $50. Arguably, some of the best shaving razors can be had for $25 or less in the Old Type, the New and some of the user grade adjustable razors. Just narrow down the year or period of what you want, look on the Mr. Razor site to identify what you want then browse ebay or our own BST.