XP Deus All Three Coils (9" currently), Tesoro Vaquero 8x9 and 5.75" DD coil, Fisher F70, White's Spectrum XLT, White's IDX, Garrett AT Pro, Fisher 1265-X, Fisher CZ5, Fisher CZ6, White's TM808, White
Patty if you have one...send it to PCGS or NGC for authentication and grading. It is a small investment but when you go to sell it, encapsulated with the grader's rating and grade; you will get a premium vs just selling it outright.
This is one of the rarest Memorial cents and has always commanded a strong price!
If you got it from circulation, then it is worth one cent. It is the proof cent without an S that is valuable. There were over 6 billion 1990 cents made at Philadelphia for circulation, these have no mintmark.