There is more to most clubs than discounts at races, and training.
Most clubs also take part in league races against other clubs in the area, and some run a regular handicap race. These events are not normal open to non-members.
So far this year I have ran 7 races and not had to pay for any of them. If I wanted to with my club there are over 30 races I could enter through the club and not have to pay for any of them.
I had not consider this when I joined as I only joined because:-
1. My kids where members.
2. I wanted to do the odd training session in a group.
3. I wanted to save the £3 a time I was paying for the monthly 5Km handicap.