I know the family cost for LOS was $45. Seems like the daily cost was around $10. I lift weights, too, and ended up bringing a pair of 15 pounders, which I made do with for the trip. We drove, though.
According to a brochure we have from our 2001 stay a "1 day membership is $15 and an individual length of stay is $25.00". So if you are going to use the facility more then once go with the individual length of stay.