The price of not subscribing is drastic.
Paid subs manipulate non-paid subscribers by "sitting on" their games in lost positions. With only a six-game maximum, non-subscribers can be frozen for seemingly endless periods of time.
A non-paid sub might take a game in good faith, only to find that the paid subscriber was sandbagging, using an engine, ends up in a lost position, then moves as slowly as possible, and even taking a month off on vacation, while still moving in other games. The non-paid sub sits with a small handful of games, many of which are barely moving at tall. Add to this the joys of clicking through advertisements, and it's easy to see why $30 per year is a very good deal.
Of course, you have to really love playing chess and lots of it, or it might not be worth it.