Wow - I suppose that makes me a real 'old'-timer.
I started keeping fish as a teen in the mid-'50s - so it's been about 55 years - it's been on & off though, both fresh and saltwater.
In my late teens, I maintained about 15 FW tanks, mainly breeders, ( bettas, gouramis, angels, barbs, tetras, and others) and sold 3 or 4 month old fry to LFS's for next to nothing - .10 or .15 cents, if I remember right, is the most I got, even for Angels - which they resold for .75 to $1.00.
Strangely enough, in the mid '50s - neon tetras for example, cost more than they do today.
What really got me into discus was when I lived in Singapore for a few years in the late '70s, and visited many discus breeding farms in Singapore, Malaysia, Thailand, and Hong Kong - that got me really hooked !
Of course, you could buy an adult discus there at that time for under $5.