We were shocked the first time ourselves. Charts are expensive, because fewer people are
buying. The merchant
shipping gets buys them because it's a requirement. They are definitely big part of a
budget, if you are
buying originals.
I don't know about charts on CD. You need to plot on them etc.
Some people get copies which are good (if they are good copies), no color, but better than nothing. Try to ask around if you can get copies. If not than electronic charts would probably be cheaper solution, but you should be prepared when computer or chart plotter fails with a backup, e.g.
laptop for computer or second laptop if you navigate on laptop.
Also you don't always need full set of charts! Get what you need for a month or two and then you might be able to
trade with people.
Good luck