I urgently need to get some money, I have some collectors coins and before taking them to the coins place in Houston (I-10) I need to know how much I can get for them without being ripped off.

1 silver dollar - year 1887
1 silver dollar - year 1878
1 dollar liberty - back says 1776-1976
1 collector dollar coin - year 2003 - 1ounce fine silver

Please help me, I need it urgently.

My great grandmother passed away and i got this necklace that has a 20 gold dollar coin from 1776. how could i tell if it was real or a replica?