If your 1887 dollar has any wear at all, even though it looks really nice, it is probably worth around $20. If it has absolutely no wear (an "uncirculated" coin) it is probably worth $30-$50.
As mentioned, there are varieties that are worth much more. Also, an especially pristine example of an uncirculated coin can be worth considerably more.
Another thing to look for is a "mint mark." If it has one, it will be on the back under the wreath. If it doesn't have one it was made in Philadelphia. If it has an "O" it was made in New Orleans and is worth slightly more. If it has an "S" it was made in San Francisco and is worth even more.
A picture would help us give a more accurate estimate of value.
Your 1891 nickel is most likely worth $2-$4, based on your description.