Well they have a promo gift right now. It comes with a free TDS meter :)

I wouldn't get any replacement filters, you can find them easily enough locally. Definitely get a TDS meter, mine is inline so I know what it is whenever I make water.

Might want to get a water report from your supplier and confirm what the water pressure in your house is. This will help you choose the proper system for your needs.

Here's a link to some FAQs that will answer some of the more important questions with regard to an RO system.

http://www.buckeyehydro.com/faq/

Thanks for all the information!!!