What should I expect to pay to have a new 8 gear Shimano 105 cassette and a new chain installed on an old but classic bike?

Cost of materials and labor? It will be interesting to see how your answers compare to local bike shop quotes. I would do it myself but really don't like working on bikes. I might be talked out of having someone else doing it if someone here told me it was easy which it likely is.....

Thank you!