I’m the one who mentioned that N scale is cheaper. The easiest way to verify this is to go to the Atlas website at Atlasrr.com and compare the prices. They sell O, HO and N.
Yep, I just double checked on the web site and N scale rolling stock/cars are less expensive. HO and N scale locomotives are priced about the same, but not cars. The most expensive N scale car I saw was $18 and change. I didn’t check every single car. I did, however, check the prices of the same model in HO. The corresponding car in HO was $26 and change. I have read and don’t doubt that to fill up the same area costs roughly the same amount of money in any scale. I’ve never checked; not sure how I would be able to verify that. Hopefully this gives you a better picture.