It appears that the AHM trolley was introduced in early 1976. That ad was snipped from the February '76 issue of Model Railroader and it looks like there was also one that month in Railroad Model Craftsman. $8.88 US; an internet inflation calculator tells me that translates into $38.20 US ( ~ $47.25 CDN) in today's money. What did I pay in either '76 or '77 when I bought mine at George's Trains old Mt. Pleasant store?
$16.50 CDN = $67.45 CDN today!