Its starts at $10/month but they have other premium membership. Activation fees are listed on their website.
If you want a "Peak" membership with all the benefits along with guest access, it's $19.99 a month - still very much worth the money. You can bring a friend, use the tanning booth and the hydro-massage bed all with this membership. Along the way you can always get involved in fitness/yoga classes, which are part of, I believe, a regular membership.
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