One kit of three floor stand seat feet is $149, including shipping to Sacramento areas.
You are not buying the seats here, just the floor stands. You can usually find the seats on
Facebook Marketplace, https://www.facebook.com/marketplace/sac/search/?query=arco%20arena%20seats
You get three brackets that allow full use of your seats and hardware to attach.
All you need is a 9/16” wrench to snug up the nuts.
Holes are provided in case you want to bolt to a dock etc.