The person now offers $ 6 600 147000 miles

Good condition 7000 Fair condition 6150 at 147000 miles

Go to http://kbb.com or http://edmunds.com and check it out for yourself.

Not a bad deal. l have a 2001 I30t, that had 69,000 miles when l bought it last year and l paid over $13,000 for it.

I'd say that is a reasonable price, of course l do not know the condition of the car. Either way, l have a 2000 Infiniti I30 with a little over 116K miles and, according to Blue Book, it could sell for about $8000. If l were u I'd thoroughly check the car to make sure it does not have any problems & if all is well then I'd buy it. I've had mine for about 7 months & there have been no major problems whatsoever. l can, however, spot age-related failures but nothing to the extent of making me worry ie. engine, transmission, suspension, etc.
Double check the car & if everything is right then go for it.