They can't take any money from you unless you give them payment information. All it does is remove access to your account after the first 7 days, until you decide to pay.

i've not used match.com so i do not know their procedures but without a credit card number it might be hard to bill you.

try http://www.pof.com/ - they do not charge.

and maybe you'd like to go back and cancel your trial account before the 7 days is up