With a free account you can create a single form and collect up to 50 responses. For more you'll need to purchase a paid subscription. Please note that we're currently running a special where you can try a paid FormsCentral account, risk free, for 30 days and the cost is only 99 cents.
Is the 50 ressponses per month?
It is a max of 50 responses at any given time. If you export then delete some responses for example you can make room to receive more responses.
Hope this helps