Comes down to service intervals and generally how well it has been treated. If you say it has been serviced every 10k, ask for books. Even at that mileage, the B18c7 is generally bulletproof IF LOOKED AFTER. Does it blow smoke when your foot is down hard on the pedal? Major service is big, usually timing belt, water pump and all other major components and can come to well over $1k. Use that to bargain down.
I recommend a compression test and leak down test to give you an accurate indication on how healthy the motor is.
If it drives well with smooth power delivery and has no gear box crunches, i say go for it and enjoy