There are still plenty of great deals on eBay, but just like other treasure hunting you have to put in the time and do the work. I like all types historical photographs including daguerreotypes and tintypes. My favorite method is to search old tintypes and select "buy it now" and click "newly listed". Then I sit there for 2 or 3 hours and click refresh every 15 seconds to see the new items were just listed. My best find was an important outdoor quarter plate daguerreotype (listed under tintypes) that was quickly sold to a Historical Society. I paid the price of a common Morgan silver dollar and received a price equal to just less than 3 ounces of gold. You have to be very quick with your buy, because on this refresh three wonderful photographs popped up but by the time I completed my first purchase the other two had already been sold. All three photos had been bought within 1 minute of being listed. Another good buy was a studio tintype of a man sitting in a chair reading a paper. I checked the photo with a loop and the headline was "Abraham Lincoln Shot".
There are still good buys so put in the time and good luck!