I’m tempted to say Gargraves is the least expensive non-tubular track, but thought it would be a good idea to list all non-tubular track. Here’s what I came up with:
Atlas Industrial Rail
Atlas Nickle Silver
MTH Realtrax
MTH Scaletrax
Lionel Fastrack
Ross
Gargraves (plastic tie or wood tie, phantom or regular, tin rail or stainless rail, rigid or flex)
I probably missed some.
Probably good to shop around a bit, but I’m guessing Gargrave flex track is least expensive. With a 5X9 layout, you may want to go with sectional track for the curves and I suspect GG is also the least expensive in that category.
Regardless of cost I would skip the MTH track since I don’t know if it will be available in the future. I would also skip the Fastrack (too noisy).
Last time I bought new GG, I got it from Just Trains of Delaware. They have it drop shipped from Gargraves. I thought the price was pretty good.