most important good rates
There is no such thing, if you have to ask how much per minute, you can't afford it...
I guess you want a portable one as you have no 110v outlet? Inmarsat are as far as I know the only provider left and I am not sure if they still have the portable one, have a look at Giggle.
Voice calls are roughly 1-2USD a minute with data calls 10-12USD a minute, you can get a better deal if you buy more airtime or more handsets.
There are a few countries where Satphones are not allowed, India comes to mind.