I have a '00 Boxster with 65K miles on it so far. It still runs very well and I just had my first "real" problem that I'm fixing right now.
This is the first car I have ever owned that after 2 1/2 years I am thrilled to get in it and drive. The Boxster is my wife's DD and she feels the same way. I've had it in the garage for 2 weeks doing our first real repair in the evenings and every day I hear "will my car be ready to drive tomorrow?"
The maintenance is not bad if you do the regular things like oil, filters, belts, brakes, etc. yourself. We put about 20K miles/year on it and over the past year since doing the maintenance/repairs myself the cost was about $1000. That includes maintenance of oil & filter, air, fuel & cabin filters, serpentine belt, brake pads, wear sensors and rotors front and back(about every 30K miles for pads, 60K for rotors on mine), brake fluid change, differential oil change. It also includes repairs of replacing the temp sensor in the engine compartment & currently replacing the coolant tank and all coolant hoses while I'm in there.
If you don't do those things yourself, the cost is about triple overall, depending on the item.
The most important thing to do before buying a used Boxster is to have a PPI done by a dealer if you can or at least by a "Porsche specialist" mechanic that works on Boxsters all the time. They should be able to tell you anything and everything about the condition of the car. That's probably about $200 at a dealer and $100-$150 at a specialist.
Get the Boxster so you can enjoy your drive to work every day, no matter what the weather or traffic is.