It would depend upon which 4 coins are in the set.
How much is a 1960 Hong Kong Modern Uncirculated Type Set worth
The 1977 US Mint Set (12 coins) has a retail value of $10.00
according to collectible coins guide, it is worth about $40.
they are only worth as much as some is prepared to pay for them
The question don't specify the country or the denominations of the coins. Post new question.
the coins is not worth anything but it is a good investment in the futer
As of today each coin is worth about $18.00
Anything from the Franklin mint is overpriced and not worth nearly as much as their sales prices. The only coins from Franklin worth anything are those made with silver.
Please post a new question with the coins' dates and mint marks.
There are no such things as 1967 Canadian Olympic coins. Perhaps you are thinking of Centennial coins?
Coins in proof sets are generally worth a bit more than coins used in general circulation.