I have noticed a scarcity of axes more that the price increasing. I've got probably a dozen people looking for axes for me. And i created a problem for myself i didn't anticipate! Now a couple of them go to yard sales and buy em for 5 bucks and sell em to me for 10! lol. But what they tell me and what I've heard from people and dealers myself is that old tools of any kind, especially axes, have recently(in the past 5 years or so) really taken off and everyone is after them. So I've given up hoping to find many and I'm networking to find axes. And while it may have a down side or two I've got axes coming in all the time. It's still fun to go look on a Saturday morning though.
A few weeks ago I was birdwatching in my neighborhood, doing a 1.5 mile traveling count that had me walking up/down on the two streets that are south of mine. I imagine usually it must look weird to people to see a guy walking along the street with binoculars, staring into the trees in their yard, so I always endeavor to not be creepy and be personable/non-weird during any actual human interactions.
Anyway, while I was stopped staring into some pine trees in the backyard of one house, a guy came out of the garage carrying a couple trash bags to the curb. Endeavoring not to be weird, I said hi and remarked on the "estate sale" sign that was posted in the yard. He offered that it was his mother-in-law's house, she had died in late-fall and they were getting ready to sell the contents of the house, before selling the house itself. I asked him if he had any tools, and he invited me to the garage to see what was there (the father-in-law had died 20+ years before, they were his tools, and the deceased MiL was 80+ y.o., to put this in context).
Long story short, I got a 6lbs splitting maul, a *3lbs stone mason's bash hammer, a nice Vaughan sledgehammer, a **stone mason's hand hammer [*,** EDITED TO REFLECT TOOL IDENTITY/USE CORRECTION (Thx, Old Axeman)], a flat shovel, a couple of hefty crowbar type things, two Disston saws, and two made-in-USA metal toolboxes (one of which is particularly enormous, like ... idk, a machinist or electrician's specialty box) for $20.
Ironically, I've never found an axe at an estate sale, but at least here in suburban southwestern Pennsylvania, you can still get nice tools from dead old timers at their estate sales for $0.25 - 1.00/ea.