A 1966 Topps Mickey Mantle baseball card number 50 has a book value of about $350.00 in near/mint -mint condition. A 1968 Topps Mickey Mantle card number 280 has a book value of about $350.00 in near/mint -mint condition. Condition is important.
Common flaws with Baseball cards include: rounded edges, creases, off centered, and faded color. Any or all flaws will devalue the card significantly. Professionally grade cards could double the value or more.