They're not officially free, but if you're crafty with google you can find plenty of Jepp charts out there to study. I was able to find the whole Jeppesen legend to study the symbols, and I also found nearly all of the charts for certain big airports. I think I had all of the charts for JFK, SFO, ORD and maybe one other. You can find them for free if you search around but they're not technically supposed to be free.