For Europe you can try EuroControl with a free account: http://www.ead.eurocontrol.int/

For Canada, try www.ivao.ca -> Enroute Charts. There are lower/upper airway charts

For Germany check this link and select in the upper right corner "Lower" - this will give you lower airway charts for Germany

http://vfr-bulletin.de/web20/index.htm

Alternatively you can search on EBAY for cheap offers - sometimes it's quite handy to have real paper charts ;)

Cheers
Johann