Yes, it helps to keep the value of the dollar.

Yes it helps to keep the value of dollars

Yes, it helps (to) keep the value of the dollar. - Help + verb doesn't need "TO" so you can actually omit it - THE dollar: In this case, this is more correct because you are referring to the value of the US dollar, used in comparing the values of different types of money from around the world - dollarS can be used like that when you actually talk about money (coins and bills/notes) Hope it helps! :)