I have an 1888 indian head penny in excellent condition and was wondering if anyone knew the approximate value.
Welcome to the forum. Your question can't be answered without more information. Coin value depends on many factors, including rarity, condition, mint mark (if any), and demand. "Excellent" condition is a subjective term that doesn't directly match up with any standard grading level, That said, and recognizing that the Red Book is a very poor price guide, in the 2003 edition 1888 Indian Heads range from $1.50 to $8,000. (To be worth more than $16 it would have to be either an uncirculated or proof example, and to be worth more than a couple of hundred it would have to be the extremely rare "overdate", in which the third "8" is impressed over a "7". If you can post a picture, please do so.
To give you an idea of a very nice or "excellent" condition coin as you described, take a look at this Indian Cent in AU55 condition: If your coin is like this...you may have a $40 plus coin, but ONLY if it is like this. If it like this: Then it is worth around $6. The word, "Liberty", the ribbon, and the lowest curl of the hair should have NO wear to be considered a nice, "Excellent" coin.
