sorry, supply and install a towel ring

.... and they won't allow me to supply them myself

Thanks Casa2,
As an example, the item in store is $28 and they are charging $64. Some of the things I can do later myself, but things like taps and sinks…

We are building in WA with a project builder. Any ideas on their mark ups and what is reasonable? We are looking at getting some accessories for the bathrooms (towel…