How much is a dime with no mint mark from 1967 worth?

From 1965 to 1967, the U.S. mint suspended mint marking of all coinage. Thus, your 1967 dime is a normal dime, which happens to be from that year range. As such, I will reference an Excellent answer to the general worth of coins:

"As with any collectible, a primary consideration in determining its value is its condition (or grade). Novice collectors, with some practice, can become quite accurate in determining grades for circulated coins (G-4 through AU-50). It becomes much more difficult when assigning grades for Uncirculated coins (MS-60 through MS-70) or Proof coins (PF-60 through PF-70) and the assistance of an experienced coin collector or trusted coin dealer should be sought. Another consideration is whether the coin has a mintmark, indicating where the coin was made: D = Denver O = New Orleans S = San Francisco CC = Carson City Coins struck in Philadelphia generally do not bear a mintmark. There are other mintmarks, but the above list covers most. There are many internet and printed resources in helping determine the appropriate grade for a coin. Whichever resource you choose to use, ensure that they follow the grading guidelines established by the American Numismatic Association (ANA)."