Hi. There are thousands of posts on this, so do a search to get hold of those - but I use Sea Pro Lite from Euronav. You haven't filled in your profile so I don't know where you are, but they do the UK for £99.95 - that's charts and software.
I have been looking at the Demo version. I can't figure out (a) how to place waypoints and (b) how to connect them together when I want to make a route? Are these things easy to do (I assume the answer is no).