Hi Tom,
Yes, you can join the golf club. Membership is currently at €1200 for the one course 7 I think €1600 if you want all 3 that fall under the Ola Golf banner - CdA, Mar Menor & Las Terrezas (not yet finished). There is still a nominal green fee I think (approx €7.00) even when you become a member, that I can never really understand the real reason why...??
regards
Nick