Lock customer price

How can I lock the customer price in quote and sales order, so that the sales team can only select the MSRP in the system. Currently the sales team puts in their own pricing and the MSRP loaded in EPICOR is like a suggestion.
I want to lock the price and force them to use the EPICOR loaded MSRP.
Please help.

Not sure how it all operates because I have never had MSRP to drive pricing, it is always negotiated.

That said, I would look at using field security to not allow people the ability to edit the Unit Price. If there is a manager that needs the ability to do it, you can give them access so they can override if nbecessary.