If you are buying the 03 from a reputable dealership, try to get an extended warranty. If not, try to get service records from the previous owner to see what has been replaced and what has not. If there are no records, call around to different Toyota dealerships to their service department and see if they have any records and check for any open recalls. Around 100k the timing chain and plugs need to be replaced, as well as the coolant.
If the car is cheap enough, it might be your best bet. Check KBB.com for a ballpark figure of value. I work at a Toyota dealership and there are many loyal customers with us who have over 300k on their Camry's, Corolla's, RAV's, and 4Runners.
If the car was well cared for and well priced, I would say that it is worth it, but it depends upon how much you drive. If you're going to put over 15,000 miles a year, I might consider something else, as you will hit the 250,000 mark pretty quick if you wanted to keep this car around for a few years. If you don't drive all that much, it would be wise choice.
Keep in mind that Toyotas will hold thier value much higher and longer than that of a domestic.
Work for Toyota Dealership in the rental and service department, boyfriend is a 28 year + veteran and ASE cert.