how much is a solver dollar worth??

Question

and how many are there left?

Answer 1

You mean silver dollar?
A standard US silver dollar of the types minted from 1878 through 1935 contains .77 ounces of silver. With silver at $13.70 per ounce, that means a silver dollar is worth a minimum of $10.54 regardless of date or condition. Obviously, there are some dates and mint marks that are worth far more than others, so a rare date on top grade may be worth several hundred thousand dollars.
There are probably a few million left around, so a silver dollar isn't rare in itself.