1. Circulated:
- Good (G): $1.50 - $2.50
- Very Good (VG): $2.50 - $3.50
- Fine (F): $3.50 - $4.50
- Very Fine (VF): $4.50 - $5.50
- Extremely Fine (EF): $5.50 - $6.50
- Uncirculated (UNC): $6.50 - $7.50
2. Proof:
- Proof (PR): $15 - $25
3. Special Varieties:
- 1966 Kennedy half dollar with No FG (No FG Variety): $100 - $150
- 1966 Kennedy half dollar with DDO (Doubled Die Obverse): $150 - $200
Please note that these values are approximate and may vary depending on the specific condition of the coin and the current market demand. If you have any valuable coins, you should consider getting them professionally appraised by a reputable coin dealer or numismatist to determine their exact value.