My university's amateur radio club had a large collection of QSL cards to go through. Really cool how widespread its use was; but it also shows how far reaching an ubiquitous the internet has become. Most of these were from pre-1970 and came from all over the world.

I got my technician's level license by using the 'Ham Radio Study' android app which does a good job reinforcing the concepts taught in the ARRL manual. The test banks for each level are all publicly posted and have a rotation of about 3 years for each level.

Edit: Meant to type QSL, not QST.