I just wanted to correct a couple quick things.
is probably your best option from what I've found. Maybe SSB
but I dont know a whole lot about that.
has seen widespread failure of their satellites and is essentially no longer useful for meaningful communication.
is 1.50$ per minute (not 6$) and gives you roughly 1 kilobyte per second speeds. This is roughly 1/4 of dialup speeds. The handsets can also be had for a somewhat reasonable price
Iridium is also handy because it provides actual global coverage (including the poles).
The others like inmarsat are VERY tough to use properly on a boat since they point at a geosync satellite
(like your sat tv). Also like your satellite TV this means they must be pointed VERY precisely or it will not work. Supposedly you can get auto-pointing stabilizing rigs for the dishes, but I've heard very mixed things about them working on boats and the rigs are VERY expensive. The upside to these is a MUCH larger bandwidth.
If you want Wifi to shore, your best bet is probably a Yagi type antenna as its beam is not so narrow that gentle rocking will knock you out of the LOS to the transmitter. My favorite way has always been having a small repeater when I go camping. That way my laptop
is not tied to a big honking antenna. I simply repeat the faint signal to be much stronger in my local area then walk around as I please.
To accomplish this, I know most cruisers usually like bottom dollar for their stuff, but a company called Deliberant makes some amazing weather-sealed outdoor equipment
Deliberant AP Solo
There is an outdoor access point which I have personally deployed in some very forbidding conditions without a single weather
related failure yet. It has a N type connector to connect any type of wifi antenna, has mounting points to mount it wherever you want, and again will outlast your boat on the water
Disclaimer: I have no interest in the financial well-being of these companies other than that I have used them and found them to be reliable.