That seems somewhat fair. You say CK35, which should be a gear model. The CK35hst, hydro tranny, usually costs 1K more. I would think a new one to be 17-18k for a gear. You would still have three years of warranty left and 70 hours is just broke in. How's the bucket look? Did the previous owner use it for moving dirt, for mowing, or whatever else we use them for? It would be nice to know how hard it was run. The tractor should have had it's 50 hour service which includes engine oil and filter, front axle oil change, hydro fluid and filters, and usually fuel filter. The service hours are extended after this initial service from new. Parts and fluids would be @$150-200. Also, some dealers will give the tractor a good check over for adjustments, bolt tightening, etc. I'd look it over good, from top to underneath, a definite test drive, and then bargain from there. If it's in great shape, then the price is fair.