How do you know if you need a new EGR valve or if you just need to clean it?
You obviously had a parts store diagnosis so maybe you should ask the person that put the idea in your head that the EGR was a problem for the answer. Did you know that an EGR code can be caused by numerous other problems.
Take the car to a dealership (Ford, if you have a ford, etc.) This could save you being ripped off by a shade tree operation. Believe it or not, lol, there are some crooks out there!
Bring it to the dealer, they will take it apart and find out whether it's just clogged or broken or something else - like for example, DPFE sensor on Fords
Usually it the car runs like crap at idle and beautifully any other time and you can't clean the EGR but cleaning the port in the intake sometimes helps for a check engine light with no running problems But as others said, the EGR is usually monitored with a sensor on or near the valve and the parts houses that do the free scans have a habit of convincing you the part they can sell you will fix it when usually it won't... Take it to a real mechanic shop, let them diag it for you