i've always believed that marrying for LOVE is the best reason to get married.
but if you are marring for LOVE and CITIZENSHIP, then that's not too shabby either.
if you are marrying for MONEY and CITIZENSHIP, on ther other hand, then what you are doing is probably illegal. that said, it's not an uncommon enterprise, but you should seek advice from someone who has some experience doing this because there probably isn't any legal information we can give you on this. is there any context you can provide for the original question?