You are not going to get anywhere unless you have a look at it are you? If you are faced with replacing the locks, then you have nothing to lose so you may as well try.
Remove, say, you passenger side door handle. Once you have it removed, take it inside and fit the key that fits. Then remove the screw that secures the latch to the lock barrel. TAKE NOTE ON HOW THE SPRING IS FITTED.
Then remove the barrel with the key still inserted. You need to do this to prevent the tumblers, gates, or whatever you want to call them, from springing out and losing them. Once removed, carefully remove the key and all the little brass tumblers/gates (etc etc) will spring out. You will notice that all of them will be different. Remove the gates/tumblers (etc etc) and don't lose the springs that are underneath them. Take the whole lot apart and find out how it works. It is not rocket science.
If you make a cock up, then do what you were going to originally do and replace them. If it works out ok, then with a little time, you will save yourself money.
If you do not have the required gates/tumblers (etc, etc) then go to your local scrapyard and get as many lock barrels that you can fit in you pockets and these will give you an abundance of spare parts.
Then reassemble and fit to the door handle.
Its fiddley but not difficult.
If somebody had to explain to a non driver, how exactly to drive a car, and write it all down, most would say bugger that, its too difficult. But its not, its a peice of piss once you get in and do it. Its exactly the same with most things. With a bit of common sense, most things are acheivable. Now go and give it a try.
