A normal Peace dollar should have a stylized A and F intertwined at the position you describe. That's the monogram of the designer, Anthony de Francisci. If you have any other letter there it is something that someone added separately using a letter-punch and wasn't done at the Mint.
As such your coin is worth its silver value of about $13 to $15.
Any silver dollar that has a letter or number added to the coin reduces it to the silver value only, about $12.00
The mintmark if it has one, is between the word ONE and the tip of the eagle's tail.
Carson City mint.
No mint mark means the coin was minted in Philadelphia.
The 1998-S silver matte finish Kennedy half dollar with the letter p is worth $500
There's no such thing as a "blue silver dollar". If you're referring to a blue-seal silver certificate (a paper bill and not a coin) please post a new question with the bill's date and what letter if any is next to the date.
A United States coin that begins with an S is: Silver dollar
Circulated - $1. The coin is made of cupronickel, not silver. Uncirculated - $1.25 to $1.50
85.00-100.00 on avge. Maybe a tad more if very nice.
Not sure what you mean by the letter (e), but a 1959 Franklin Half dollar in decent condition is worth about $10 to $13
It's spelled using the Latin alphabet, and the spelling appears on every single Peace dollar.
"E" is the highest series letter for 1928 US 1 dollar silver certificates. The only $1 bills with a G series letter were dated 1935. Please check your bill again and post a new, separate question.