you dont need it
i liked mine... but im a geek about numbers and I knew I would be using it almost a full year before we were able to ttc again so I threw my money into a year VIP (plus I figure it goes to help pay to keep the site up!)
if I had been actively able to TTC every single month I probably would not have spent so much on it.
It should still give you crosshairs IF you have a clear ovulation (using temps). The only reason it wouldnt is not because you are not VIP but rather because your ovulation date is not clear to it. If you dont temp, for example, it will never give you crosshairs. Or if you have erratic temps or it thinks you may be anovulatory, it will not give you crosshairs.
In my (very biased) opinion there is not a better site out there for charting, even without the VIP membership.