I don't think I would pay 600 dollars per year to become a member of a shooting range, especially one that's always crowded.. I just renewed my FAMILY membership at the Rod and Gun Club here for $55.. :P
And it's not that people can't afford to pay out 600 dollars over the course of the year, but many cannot afford to hand over 600 in a lump sum. The only way I would be able to justify spending 600 dollars to shoot would be if I shoot over 600 dollars worth of ammunition each year, which I do not.
Saving up your ammo money all year to pay for a membership to the range? Not likely.
40 dollars for a one time thing though? If it's a nice spot, as this range sounds like it is, I'd check it out.