What problems should you expect to have buying a car with 300k miles?

Looking to buy a 7 year old Honda with 300k miles cause it's really cheap. What are some problems I should expect to have?

Worn parts, contamination of fluids from lack of maintenance, failed smog test. Everything from complete engine rebuild to suspension damage to catalytic converter replacement. Even if the body looks okay, if from an area with road salt, might be rusted out.
Walk away quickly. Really cheap high mileage cars never are.

Oil consumption, bearing wear, dodgy electrics

Hi so it has now come to them end of it's serviceable life. So it would not be reliable.

Pretty much anything. Get it checked out by your mechanic. Even at a really cheap price it may not be a deal you want.

Everything.

Depending on if the prior owner maintained it well, it could be the best used car on the road, or scrap metal on wheels. Either has a mechanic inspect the vehicle, or forget about it.

Lots of things, some major, some smaller. How did he get that many miles on a 7 year old car? You should ask.

I'd have it inspected by a mechanic, as it's pretty much end of life.

I doubt taking the time to tell you all the things that are going to break on it is worth while since you are even considering wasting money on a vehicle that old.