Like that 1914 penny I lost. i just looked it up. $7.50 not so important then I bought it for 20 cents in the 1980s because that's the value it went through the bank's machine at (I was the teller).
I had an original $2 Telstra phone card in my wallet for years. I eventually threw it out. Maybe it is still worth $2.
I knew I should have bought up all the local coles's supplies of iSnack2.0 before it became cheesymite!