Post-it notes
Working as a paralegal on the sandwich year of my degree at a firm of solicitors back in 1990. (Faxes were the big thing then but this firm resisted that new technology for a good couple of years; but I digress [literally just received a fax as I type this; first one in about 2 years! Spooky]).

I was tasked by Mr K to go through a set of accounts to flag up certain transactions. The accounts were literally in a big leather-bound journal and it was quite an important task as those pages then needed to be copied as evidence in some hearing or other. Post-it notes were comparatively new back then so probably quite expensive in the office-stationery scheme of things. But it was well known that Mr K was the only partner who had such things - proudly displayed on his desk in a post-it note holder. Behind him was the view of the car park which contained his classic Lotus and his Ranger Rover.

I waltzed in and asked for some post-it notes to stick on the relevant pages which elicited the response, "can't you just use cut up pieces of paper to mark the pages?". "No," replied I, "the paper might fall out and you would not know which page to copy. Post-it notes would be ideal."

After an exchange of 5 minutes or so (probably all chargeable to some client or other), I managed to negotiate the release of 3 whole post-it notes that I could, "cut up and make into smaller slivers because they are quite expensive you know!"
(Gusofnavarone always makes a map of france from sarnies, Wed 9 Mar 2016, 10:20, 3 replies)