ok so you are looking for a car in that price because that's what your budget is in general? i'm guessing that and nothing wrong with that at all. but so, ideally, go with an 06, but from your side of the table, that's not what you would prefer.
if i'm wrong to this point, disregard the rest!
so, you kind of get what you pay for, and i don't pay a lot of attention to blue book values. i'm also not an expert in this field (prob because of the former lol).
but... take the car out and see what's what. if you can't tell, take it to a mechanic for a prepurchase inspection- usually $60 max at a brand place like firestone...
generally speaking, you get what you pay for. so a 2001 selling for $6k is, on odds, in better condition that one selling for $3.5k
but, steals are out there. generally the people that know their stuff get the steals, and those that don't get had.
long, but i hope somewhat helpful
so you can see i can't answer your question about what it's worth.
but, the major problems with this as i know are the coils- if you are mechanically inclined this can be a relatively inexpensive repair. also i'm sure there are many others, but being the owner of one that is 201,000 KM (not miles) on a V6 (for the record i totally disagree with not buying a car in this day and age with more than 100K -miles or km- but that's for another thread), what i've had to change is the coils. my hydraulic fan is failing, but i'm topping it up and hoping how far i can get. the LS uses a hydraulic cooling fan because the alternator mapping could not work it into the electrical system in the first gen (2000- 2001) LS. other than that, my passenger side bearing on the front wheel is starting to make noise, and it's going to cost $300+ from dealer because the ABS sensor is there. finally, the transmission jerks when going to R, and shifts 'oddly' when driving. i took it to dealer, they say $700 for solenoid. took it to mr. transmission in toronto, say no errors returned, but agree with rough shifting. suggestion: leave it.
i have, and no problems except for weird changes, but no slipping.
i've read this is a recipe for transmission failure. i'll take my chances.
on the other hand, look around, that solenoid is not that hard to replace
i'd get the car if it runs well, and if you are willing to, over time, spend time/money to bring her back to top shape.
don't forget: this was motor trends 2000 car of the year. that's impressive
