well in game usually 100 cartel coins is 75-100k credits.
example: cathar warstaff costs 400 cartel coins, usually sells 300-400k.
1 mill on jsp = 500 fg.
depending on current in-game values on the server you play on (prices vary daily and server to server based on supply and demand.) spending about 1200 cartel coins u should be able to get about a million.
in my opinion i would say 1200 cartel coins should be about 500-600 fg.
these values are based on the my experience and the value of stuff on the server i play on (the bastion). other people may have a different opinion.