Spain does not usually deal in Club Memberships as we know them here in the Uk.
What you actually purchase are golfing rights. These give you reduced green fees, preferential tee times, perhaps a locker in the changing room etc. and there may be a few rounds of golf thrown in but not the ability to play the course for free all year as in this country.
For this reason amongst others, many people join a local golfing society and then pay reduced fees when visiting various courses as part of a group booking.