It is a DIY job for a competent person with a set of tools and a Haynes manual. Who is Jack is 100% right as it makes sense to put a new clutch in while the opportunity exists. Unless the car or clutch is very new.
Thrust bearing on what car...and I assume since you are from NSW you mean throwout bearing for clutch, not crank shaft, camshaft or any of the others...Americans would assume the engine crankshaft bearing that controls end play...if that's the case you're looking at thousands of dollars..it's never just the bearings that's bad...but let's go with what the non American English speakers are calling the thrust bearing...( the thrust bearing assembly, we US folks call the clutch release or throwout bearing)
Some vehicles it's a simple DIY , and some you'd want a transmission jack, lift or hoist ....the price would vary by vehicle, you'll want to change all the pieces while it's apart...the parts are the cheap part of the repair. The 350Z here in the US about 800 dollars for complete clutch replacement...you can do complete clutch yourself for about 250dollars
The thrust bearing rides against the crank keeping it from walking back and forth.I would suggest taking it to a mechanic or engine re builder and letting them do it because you will need to use a micrometer to determine the actual amount of wear on the engine block and crank. Too much wear or damage to the crank or block give you a nice lawn ornament. If you decide that you want to tackle this for yourself then get a good service manual and speak to a local automotive machinist in your area and ask him for some tips. The price for doing this is about the same as rebuilding an engine
both. though a competent DIY mechanic can in most cases carry out this work it is normally not a good idea both for work and equipment needed and even special tools on some cars etc.
ideally get a quote for your car from both dealer and specialist in clutch replacements. costs vary according to car and parts .
its never worth just replacing bearing unless new clutch was fitted within last year or so. often we have later to again have work carried out doing so so cost saving for doing all wrk at same time are worthy.
There is a big difference between changing a PILOT bearing and a THROW-OUT bearing The thrust bearing is the final engine main bearing.
For a person that doesn't have a clue what a thrust bearing is I'm waiting for the next question!
It is a gearbox out job, so unless you have a lift it will be hard to do. Also worth replacing the clutch at the same time as the gearbox it off to save yourself money in the long run.
Is it a DIY or a mechanics job? And how much roughly would I be in for price wise to get it replaced?