If you want to try it don't make the mistake I did. I signed up for the 2 day trial they offered online. When that ran out I signed up for a monthly account. The next day an email came offering the one month trial, which I can't use now that I've paid.
I am still waiting for my one month trial (after the 3-hour expired).
Still waiting for their email too for other questions. Wonder if they will come back to me. DS8 is pestering me because he wants to finish his Pre-Algebra Pie. I will give it another day before signing up for a month's use.