I was only 12 years old in 1978, so all my firearm dreams were limited to newspaper ads. I remember constantly saving the sporting goods section of the Kmart ad, with the Marlin 60 circled. It was around $59 if I recall. However when I turned 18, within a few days after, I went to Kmarts and purchased my first firearm, which was a Ruger 1022, for around $118 plus tax.
I have a Charter Arms AR-7 .22 that I bought around that time for, I believe it was $79. I saw one the other day, (although I believe another manufacturer has the patent now and is making them), for $279 on sale.