When I was new to the hobby as a teenager in the 50s about the cheapest kits around where Varney. The Varney flatcar ran $1.99 at the time. Now at the same time, gasolene ran 25 cents a gallon and you could get 15 cent McDonalds burgers. Minimum wage was a buck then so I worked 2+ hours to clear enough to make the purchase of a Varney flatcar kit.
I have to ask when you actually bought the $2.50 Athern and $4 AHM?
Have you tried the moidel RR shows (e.g. Greenberg, etc)? There's usualy a host of used stuff available at bargain prices...especially as the show gets close to the closing hour.
Yet one can still find inexpensive "train sets" if you look for them. I don't know if they did one this year, but Shoprite foodstores usually has an annual Christmas set for under $50...which is then marked down if any are left after Christmas.
Others too have pointed to the "scratch builders" as a way to keep costs down....especially for buildings.
Cheers, Bill S.