What is the value of a 1928 silver dollar money clip?

It is worth whatever melt is. The silver dollar is damaged and they never use rare dates (the 1928 peace dollar is rare, it is likely a 1928-S coin which is quite common) and so it would be worth about $20 for the coin. However, there is the question on whether the money clip itself is silver, usually the clip would be marked "STERLING" or 925 if it is silver. If the clip is silver, you have added value with whatever the weight of the silver clip is.