I think the cheapest way for you to go about this is a oxy + propane setup. You can sub the oxy for an oxygen concentrator if you want. Propane is a cleaner gas to work with / less dangerous / doesn’t create soot. It doesn’t get as hot, but I’ve been using it problem free for 3 years now. I think a lot of other builders use propane over acetylene too.
I find a normal user-owned Prax-Air oxygen tank lasts 3-4 frames total. If you’re just doing brazeons and the occasional dropout, the tank will last you a while. At my local Prax-Air the tank refill is $65 Canadian.
I use a Smith brazing torch. I can’t remember the model, but I have a bunch of tips and switch depending on what I’m doing (silver vs bronze vs fillets vs whatever).
If you are mainly interested in brazing bosses, I’d recommend a Minitherm torch paired with a propane tank and an oxygen generator. I personally like a bigger flame when brazing forks, but my friends, who braze way more than I do, absolutely love it. It’s very wrist friendly.
I had one of those mini tank setups for a handful of years I kept around for repairs and demos elsewhere than my shop. It was fine, the regulators are kinda cheapie, but the setup will get you by as a hobby.
The main consideration is some/a lot of welding suppliers won’t do tank refills on those minis. I’m not sure of the reason, but it would be worth double checking with wherever you will locally get your gas before investing in the setup.
For what it’s worth… I think most people are using the Victor J28 or the Smith AW1A or clones of them. If you use a torch hanger it doesn’t have to be pretty but please make sure it’s secure. This is my J28 and hanger.
My bottles are strapped to a hand truck. They are taller than this setup, but don’t really take up much more floor space - if any. If you get a decent O/A setup you might use it for bosses too. I’m a brazer who has to borrow a tig welder for an occasional job; funny to hear about someone in the opposite situation!