Great topic. American sawmakers of the late 19th century to the 1940's such as Disston, Simonds, Atkins and Bishop are usually a good bet for quality goods. Condition and lack of abuse is key to getting a good user. Avoid sawplates with rust pitting, sharp kinks and nasty teeth. Prices at flea markets will be cheapest, antique malls a little higher, restored saws by tool guys higher still and collectors with restored saws highest. That is a range from $3 to $150 for usable saws. So as the price diminishes your commitment to restoration must increase. Carpenter saws range around 24 to 28 inches and docking saws 30 to 36 inches. Filing is a whole other world of preferences but 4 to 6 tpi for rip, 6 to 8 for crosscut and 2 to 3 for docking. Different tooth profiles and sets for hardwood, softwood, green and dry wood.
Disston saws from different periods and models were tested for steel formulation, it was found that the steel was of a relatively consistent nature. The major differences were in the shape, taper and polish of the various models.
New sawmakers seem to specialize for cabinet makers and well heeled collectors, so I believe you could acquire a chest of vintage saws and maintenance supplies, for the price of a couple of premium saws.