using
saildocs you can get the gribs for free - of course you still have to pay for your connection time.
There are a couple ways to get the gribs from saildocs - tyou can just send them an e-mail format request (Instructions on the website or sailmail/airmail will automatically do it for you) and they automatically/immediately e-mail the grib back, or you can use the free "Viewfax" grib viewer which has an 'online' grib request function, or you can use any of the various charting programs that do
weather routing (I think expedition is best but
maxsea is also good) as they have built in grib request functions.