Dear Log,
Cassettes were $6.99, Albums were $7.99. Items from the back catalog that weren't really hot sellers were $5.99 on cassette, and rarely available on vinyl. Stuff you don't want to admit you own was $2.99 or $3.99 or so. If you got something on sale, it was never more than $1.00 off, and a discount that deep was rare, generally limited to something the distributor was trying to make platinum. Double albums were generally $13.99 on cassette, much as you would expect. (I forget how much double vinyl was, probably $15.99.)
CDs were $14.99 and up. But it was OK, because they were for yuppies who had money to burn on a CD player that cost a couple of hundred dollars, and a primo stereo system to hook it into.
There was talk back then that the high price was temporary -- it was caused by artist backlash (not wanting to move away from vinyl), low manufacturing capacity, and investments in new anti-theft devices. Then there were rumors that artists were being offered twice the standard royalty rate to get more titles on CD and create a market. There was talk that manufacturing capacity would increase RSN. And distributors came out with "the long box" to foil shoplifters.
The year? 1985.
CD prices have come down a couple of bucks since then, and the value of a dollar has dropped. But it was easier to buy music when you had $5 and some change in your pocket, or you could break a $10, buy the new Aerosmith and have some money left over.
Funny how the prices never came down. Funny how music stopped being an impulse buy. Funny how the distributors are crying "mercy".