If you have to have a repair carried out on your car, then it may be worth trying to source the parts required yourself. You need to check with the mechanic or garage that you are going to use that they would be happy to fit parts from elsewhere. Most garages will do this, but obviously will not put any warranty on the parts supplied.
There are many places that you can find car parts online such as eBay, Gumtree and Euro Car Parts to name a few. If you are buying second hand car parts, check to see if they give you any warranty, as once you have purchased it you may find that it does not work and that you have lost out on your money. Also check if you can return the car part if it is incorrect.
To source car parts yourself, you really need to be confident that you know what you are buying.