Sportsman's Guide offers the HME Treestand Coiled Cable Lock 3-Pack for $6.99. Plus, coupon code "SH1237" bags free shipping. That's the lowest total price we could find by $5. They feature 6-foot coiled cable with matching locks and three identical keys.
Note that a 99 cent Package Protection charge will be added in-cart. You'll need to remove it.