I started collecting in the early 80's. Biggest differences:
There was no internet, Ebay, pinside etc. Games were bought by looking for or posting ads in local papers or trading magazines, by looking in the yellow pages for operators and visiting their warehouses, and by visiting distributors like active amusement, eastern amusement, and banner in phila. Also by visiting arcades like space port and Aladdin's castle and either asking what was for sale or getting on their mailing list of games for sale. There was little if any competition for games and few sellers to compete with at christmas time. You could buy anything you wanted, limited only by your own wallet and physical strength to clean out warehouses!

EMS were $50 all day long. All titles with rare exceptions. Later on when they first came out, digitals were expensive, but started to get very cheap in the late 80's and early 90's. I bought games coming back from Europe out of containers at ridiculous prices. Af for 900, wcs 450 etc. I was happy to buy a nice addams for 1000 and flip it for 1800 or 2k. If ida only known...
Parts were almost non-existent in the late 70's and early 80's. Countless pins were parted out because a backglass was broken. There were no repros then. Plastics were unavailable except from a parted game. Wax, rubbers and coils you could get from steve young at pbr or Steve engle at mayfair or maybe the local distributor - but that was it. Collectors dont realize how lucky they are today. Almost any obscure part they need available from one or more vendors. And if it's not, somebody has the technology to make it from scratch!
You waited anxiously each month for gameroom magazine or pinball collector to be delivered so you could read a how to article or two and most of all read every single classified ad word for word looking for a good deal. I would read and re-read those ads calling sellers and trying to make deals. Then start all over again the next month.
In those really early days, there were no pinball shows. But there were the gameroom shows in phila, hackensack and Chicago and what an experience they were!! Parking lots with dozens and dozens of trucks full of pins, jukes, slots, traffic lights, 50's memorabilia of all kinds from all over the country! And inside, booths of the finest shopped out gameroom stuff you ever laid eyes on! Bright lights, neons and chrome everywhere! What fun they were!! Its still fun today, but with way more competition. And, oh yeah, just add another zero (or 2) to the prices!