I'm not a real experienced Walker person. But I do know this. They all ride and gait differently. Just like trotting horses will have different trots, rough, smooth, etc, gaited horses all feel differently too. And they can be very
smooth, but just because one feels a certain way, the next one you test ride may feel very different.
I've ridden a couple of Walkers and a handful of Foxtrotters, and I swear every horse has a different feel to them. Some have short, quick, smooth steps, others are long strided. Some feel very level, some undulate like a camel. So you have to test ride each horse as an individual. There doesn't seem to be a universal "feel" to the gaited horses I've ridden.
All the gaited horses I've ridden have been barefoot (because me and my friends just trail ride). And all gait barefoot. So yes, any Walker should be naturally gaited and gait barefoot, providing that they have tough enough feet to go barefoot (just like any other horse). But shoes aren't required to have a nice trail gait.
So that is my prospective, coming from just a trail riding background.
For price, I would guess it has a lot to do with what area of the country you are in. And I bet Florida is expensive! They are fairly expensive out here too (Arizona).
For instance, and I've told this story a few times, but I dreamed of getting a gaited horse because 1) I like the way they feel and 2) my mustang could never keep up with my friend's gaited horses.
And I talked to this couple who had Fox Trotters and they assured me I could get a nice one for $5000. Well, I pretty much went home and cried, because I didn't have that kind of money to spend on a horse. My budget was more like $2000 max.
Low and behold a couple months or so later, they same people told my friend who has the gaited horses that there was a Fox Trotter mare for sale for $500 who was going to go to auction if she didn't sell before hand. And my friend new I was dying for a gaited horse, and that is how I got Isabelle. I just totally lucked out. I know the market has dropped, but the cheapest I have even seen anything like a Walker or Fox Trotter advertised for was $3500. So it was just totally meant to be. And she came pregnant and gave me my first foal, but that's a whole 'nother story!
Anyway, other folks in other parts of the country act like you can get gaited horses cheap, anywhere, all the time. But that certainly is not the norm in Arizona. I suspect they are cheap in the states that breed them the most- Missouri, Tennessee, Arkansas, etc.