Best way to find out exactly what services the car needs or has already had done is to see maintenance records (if there are any) and to pay a trusted mechanic to inspect the car before you buy it unless you're highly knowledgeable about car maintenance yourself.
Most mechanics will do an inspection for $100 give or take. During the inspection, the mechanic can tell you exactly what needs to be fixed or replaced, what work has already been done, and how much anything is going to cost to fix.
You could get off cheap if all major maintenance has already been done, or you could get stuck with a hefty bill if some major preventative maintenance items haven't been done yet. Things like replacing a timing belt / water pump can easily cost over $1000 depending on where you have the car serviced and 80K mi is in the range where those items start needing to be replaced as preventative maintenance.
well 80,000 on any car is nothing when most with care can go into 400,000 and its never the miles one look at when buying a car but its the shape one is in learn how to check for signs of problems will do you much better which you can get by typing into search box
how to check used car
and following a check list
but as for bmw's they kind of high on the repair list parts and gettting someone to do the work cost you more than a ford or chevy does