Workshop prices completely overworked?

Moin, at the Malibu V300 2.0D from my wife, both drive cuffs on the right side are easily torn down and have to be renewed. She had a KVA given to a free workshop – so I dropped the chinlade: According to the workshop, the cuffs are not to be obtained individually – so a new drive shaft for beaten 500€ plus assembly. Timing belt change (according to Opel at 60,000 of the every 5 years due) would also be at approx. 500€ and service with oil and filter change 300. all Have you already had some experience? How do you look at it? Have you seen: The timing belt set (ContiBelt) should cost 250€ at the workshop – in the net I get the one for well under 120 incl. water pump. Oil filter would be at 50€ – in the net for 20th air filter should cost 30€ – in the net for approx. 10. And all brand parts like man or grinding filter. Was for years not in a workshop and am really shocked about this violent customer 60-100% surcharge. I prefer to buy the parts and do it myself. Is it the same in your workshops? LG – MT