What brazing equipment works best for building bicycle frames has been extensively written about on the different frame building forums including the one David mentions. They will give you a lot more detail then my following cliff notes version. The small portable tanks you noted will provide enough gas to make one frame. I would not buy any of those all-in-one units if I was starting from scratch. The torch handles that work well with a cutting attachment (the most popular reason to buy an oxyacetylene outfit) are bigger than anything I like. I prefer using propane with an oxygen concentrator for convenience, safety and cost.
Here my recommendations. There are a lot of other options. If I am using a BBQ propane tank (enough fuel to last almost forever) I would get a either a Uniweld 71 or Victor J-28 torch handle. They require a Victor (or Gentec clone) UN-J mixer/elbow with TEN (that is a designation not a number) tips. I would get at least the TEN-2 and TEN-3 but if money isn’t tight I’d get the 1 and 4 also. On the gas supply end of the torch handle I would put check valves.
I don’t like heavy rubber hoses so I’d buy light hoses from TM Technologies. That 10 foot length isn’t long enough for me so I would extend it with T grade 3/16” rubber hose to the tank and concentrator. I would put in a flashback arrestor between the end of the hose and the propane regulator. There is no need for one on the concentrator. You can buy everything from the torch handle to the tank online at TM including the regulator.
An oxygen concentrator (the medical device that lets old people breath almost pure oxygen) can be bought on Craigslist for an average of $200. Some of my frame building class students have gotten them for under $100. They will give you an endless supply of oxygen without the need to buy a tank and regulator. M&M Medical in PA sells refurbished ones with a 3 year guarantee for $300.
So If I get all of this new except the concentrator I have a bill of somewhere around $750 depending on if you buy real Victor stuff or the cheaper clones.