In the days before electronic navigation, I used to get my charts from freighters. After 6 months or three corrections, their charts were no longer useful and were sent to "the cancelled chart drawer".
I'd go up to a ship in a port and ask for the second officer (third on Norwegian ships), the navigation officer and ask for cancelled charts. This usually led a a fine friendship, meals and laundry aboard.
After a few years I had a pretty complete world portfolio of charts, for free. Obviously, as cancelled charts they were no longer up to date, but hey, I wasn't sailing a 70,000 ton ship drawing 22 feet, so with due diligence, they worked very well.
Biggest problem was weight and storage; a thousand charts is a BIG pile.
Today I use the Garmin Blue Chart Data Cards and I've found them to be spot on (actually better than paper for accuracy) everywhere I've used them except the ICW. A bit pricey but lots smaller for storing.
Just as an aside, are you aware of the EU Shengen Laws? They are keeping us from sailing to the Med. F-ing politicians!
"Any idiot can make a boat go; it takes a sailor to stop one." Spike Africa aboard the schooner Wanderer in Sausalito, Ca. 1964.