Hi Newbie,
Depending on your water depth, the size of your boat, and what material you prefer, moorings run from around $1,000.00-1,600.00.
Usually galvanized will last 3-5 years depending on its location and use but its good to inspect it yearly for unusual wear prior to the start of each season. Stainless should last 10+ years but again its important to inspect it prior to putting your boat out for the summer to make sure all of the cotter wires are intact and the chain is in good condition.
Feel free to send me an email with the type and size of boat you have, water depth, and type of chain you'd like and I'll put a formal quote together this evening.
Thank you,
Mike
info@winnipesaukeeis.com
603-707-4677
http://www.winnipesaukeeislands.com/mooring.php