I use the Coaguchek XS ... I was given mine by ATS but they are available online (ebay seems the most competitive) for about $500. I buy strips from online medical supplies and they cost me about US$130 for 24 strips. I have seen dammaged package ones on eBay in the US (which I would personally feel fine with) but the postage to Australia makes that uneconomical.
On hotter parts of the year I leave mine in the fridge and pull the container out allowing it to reach room temperature BEFORE opening it. This is because we have days here which exceed 35C and that will degrade the strips.
I personally (with all their recalls and stuff) would not touch an INRatio with your barge pole, but thats just me
DO NOT get fooled into buying any other coagucheck except the XS because the earlier model is discontinued and there are no strips available anymore. As the technology is actually in the strips, I would feel quite comfortable with buying a used one in good condition. I see auctions where "we bought it for mom and she won't use it" a bit, so seems like a way to get a bargain if you ask me.