Break point

what problems can i expect from a prius w/ over 100k miles

the usual

As Is The Case With Most Cars, The Number And Degree Of Problems You Will Have Is Highly Commensurate With The Timeliness And Degree Of Maintenance The Vehicle Has Received.

Are you the original owner ? Has the car been maintained according to the manufacturer’s maintenance schedule ?

Other than that it would behoove you to get hold of access to the over 100 technical service bulletins that are specific to your vehicle. These bulletins written for technicians often give you the best idea of any likely or frequently recurring problems with a particular vehicle. I never buy a vehicle without reviewing the TSBs.

Do you have any / all the R.O.s that show service work performed on this car ? You can compare that with likely problems shown in the TSBs. Perhaps some have been taken care of already.

Another thing to do is to talk with mechanics who frequently work on these machines.
They often know what you should expect and can maybe advise you on things you can do to avert certain problems.

What model-year is this vehicle ?

CSA

2002 prius

At that age, I’d start wondering when the batteries will need replacement.

There is a fairly insightful article in the latest issue of Consumer Reports about a Prius CR has operated as a test over the years and one that a person in Iowa City, IA has run for nearly 400K miles (if I remember correctly) and very few major repairs.