1. Condition: The overall condition of the bill is crucial. Factors such as wear, tears, folds, stains, or any damage can affect its value. A bill in uncirculated condition, meaning it has not been in general circulation and shows no signs of wear, is more valuable than a circulated bill.
2. Grade: Professional numismatic grading services, such as the Professional Coin Grading Service (PCGS) or Numismatic Guaranty Corporation (NGC), assign grades to banknotes based on their condition. A higher grade indicates better preservation and can significantly increase the value of the bill.
3. Rarity: The rarity of a particular series or signature can also influence its value. Some series or signature combinations may be more scarce than others, making them more valuable to collectors.
4. Serial Number: Certain serial numbers, such as low serial numbers, consecutive numbers, or those with repeating digits, can add extra value to the bill.
5. Provenance: If the bill has a known history or provenance, such as being part of a famous collection or having a notable owner, it can enhance its value.
In general, a 1950 $100 bill, Series E, in uncirculated condition and with a desirable serial number can be worth several hundred to a few thousand dollars. However, it's important to consult with a professional coin dealer or numismatist for an accurate valuation, as market conditions and individual preferences can affect the actual value of the bill.