[David G4EBT]

To be frank, they're not worth anything.

I've still got one somewhere if I haven't binned it, which I used decades ago to try (fruitlessly) to interest my two sons (now aged 49 & 53) in electronics.

Modern versions of S-Decs are used extensively - particularly with Arduino projects - for electronic solderless bread-boarding using 'jumpers'. If you do a google search for 'solderless breadboards' you'll get almost 2 million hits. E-Bay is awash with them - I won't give any, links so as to comply with forum rules, but typically here are a couple of descriptive examples on E-Bay:

1) Solderless Breadboard 400 Contacts Electronic PCB Test Bread Board 400 contacts. £1.00 post free 'Buy it Now' from China.

2) Arduino Breadboard Solderless Protoboard Test Board 400Contacts Tie Points. £1.20 plus 89p post Buy it Now from a UK seller.

There are countless others, some larger, some smaller.