If you want a nice saddle relatively cheap, check on eBay
, Craigslist, local Newspapers, or tack shops for used saddles. They are already broken in and a fraction of the price!
I am glad you aren't jumping into this without any horse knowledge, I have seen too many horses or people get hurt/ruined. But, you seem to be going in the right direction :)
I've never ridden a gaited horse while it gaited, but I did have the first 5 or so rides on my aunts TWH mare(walking only, working on the basics). They are a fantastic breed, and every one I have met has been really laid back! Definitely a good choice for a first horse!
Good luck on finding a horse! Keep us updated on your search, and be sure to post a lot of pictures when you find "the one"! :)