Welcome aboard Mike Flea! All of the advice that you have received from the forum members is first class stuff. By the way, the term "stuff" is an archaic steam engineering definition from very old Machinery Handbooks from the late 1890's. Stuff is defined as steam that has lost all it's thermal energy, but that is still visible. Think WWII film noir railway stations, probably in foreign films, such as featuring Bogy and such.
As I remember, you have a potential 4' radius as your "controlling radius". This alone will determine which small scale live steamer you can "afford". It is the mechanics of your pike that that limit your buying decisions, not the depth of your wallet.
I, myself own a portable I" gauge layout that I bought from Michael O'Roark that has a 1' foot controlling radius that well handles an all up, but regauged, "Ruby" live steamer and a couple of Michel's custom built goods wagons. It will also accommodate a couple of the Regner 0-4-0's that are regaugeable to the German narrow gauge that about duplicates 1" American gauge. I displayed this layout at the Summer Stamp in 2013, maybe 2012.
My first live steamer is an Aster Frank S. 0-6-0 purchased new in 1994 for USD$999.95 plus shipping, from Trainworld in Brooklyn, NY. The locomotives that have been recommended to you are in todays dollars less expensive. This is in no small part due to the pioneering efforts of brothers Charlie and Bing and the whole Accucraft organization. They did put the price pressure on the existing live steam model manufactures and thus created the aggressive pricing that we model engineers enjoy today.
As you have been advised by my peers in the hobby: it is addictive. The restrictions of a 4' controlling can easily lead to visits to estate brokers! In my case I determined that I had enough square feet in my Japanese back garden to build a 33' by 35' elevated, double loop, 45mm pike with sufficient steamup area. The original facility was commissioned in1997. It was rebuilt in 2015. The failure mechanism was the sun's UV, and other rays, attacking the cast-in plastic spike heads. These failed over the 18 years use, and I did gain some useful time by selectivy hand spiking the failed rails. Nothing lasts forever!
In my experience the happiest budget live steam modelers are the ones who own a couple [that's two] personal favorite locomotives/consists, but no railroads. But, they do belong to a local steam club that hosts steamups during the "season". It may not be the whole enchilada, but it is the most economical way to go.
Forget the sparky layouts as most are on the ground and our steam oil ruins the electrical conductivity of their power pickups.
Mike, if you wish to go live, you can e-mail me at email@example.com
Unfriendlys be advised that I employ electronic countermeasures.