Hello guys,
sorry for my english, i'm italian.
I've this US stamp in my hands.
I'm getting crazy

because i'd like to identify it and to understand his worth but, when I go to the website of stamp world, I can see many identic stamps, with huge different values.
I can find :
1875 Zachary Taylor, 1784-1850 - Yellowish Wove Paper
21. June WM: None Perforation: 12
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1875 Special Printing - Hard, White Wove Paper. Without Gum
WM: None Perforation: 12
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1879 Printed by American Bank Note Company - Designs of 1873. Thin to Thick Soft Porous Paper
WM: None Sheetsize: 200 Perforation: 12
--------------
1880 Special Printing of the 1879 Issue - Soft Porous Paper without Gum
WM: None Perforation: 12
i'm not expert in american stamps,
i've about 30 1800s american stamps only.
Could you please help to identify it so that I can understand his related worth?

Thanks in advance for all the answers

