I think the cheapest for the xp3 is @ http://www.kensfish.com/filstarcanisterfilters.html $127 + shipping.
I got my 2217 on Ebay new from a guy in NY. I won the auction for 127.00 with shipping. It's $139 + plus shipping @ Kens.
uh oh....if the difference between an XP3 and a 2217 is only $20 ..... I think i might go with 3 2217s instead....
Now i don't mean to offend but the site is not very...professional, is it reliable?