So I have been researching this for about 18 months and finally pulled the trigger on one myself. IMO no service history 120k is too much, great service history 222k (this is my own risk assessment for a daily driver). The problem is its all the small things, I just got a 180k 07, its going to need new bushings, new front shocks, and a new power steering rack. That means if i wanted to get it back to spec it would have cost another $6k... because this $200 job and that $300 job and replacement shocks are $600 but upgraded ones will only be $900...
Get the VIN, go to drivers.lexus, create a profile, add the vin to your profile. if it doesnt have service records up until this year I would go over 4K on it as a rebuilt transmission is going to set you back $3k+ there are just so many small parts that just stress fracture with the constant flexing. Getting anything more than 400k out of a vehicle takes a lot of maint and replacing parts that wear out. Baslining all the services to where you feel comfortable with a good starting point is going to cost you a couple of hundred if you do it your self.
SO IF THIS IS A PROJECT TOY offer $4k, buy it at anything less than $5k, build it destroy it, enjoy it and sell it for scrap metal when you are done. If this is going to be you daily driver RUN LIKE HELL IN THE OPPOSITE DIRECTION.
Remember no one sells a perfectly good high mileage used car, there is always a reason... finding that reason is how you dont get screwed.
edit:
Went to the ad, those look like snow tires on it so factor in the cost of tires too, the seat looks really good meaning it has been replaced or the location would suggest a lot of highway driving. They are in the middle of no where, no dealer would take that car as a trade in unless there was some gimmicky promotion, That car is near maximum low value best case it has another 300k left realistically only another 130k and it is going to be eating parts (assuming they havent all been replaced recently). If i were you and you wanted a project toy Maximum lowball $3720 thats a penny for every mile its been driven. If they tell you to go away then take their advice.