You'll have to read your homework again, Dan! You don't, under any circumstances want to be buying circulated coins. That can be said with very few exceptions right back to the 1930s. Buy the very best you can find! That was the point of setting you 1967 as a starting point you see - as the commonest year, and the last predecimal year, you will be able to insist on top grade coins, and still only pay pennies. Then you'll be able to get a feel for what uncirculated coins look like, and thus be able to be choosy when you get to the harder dates, which is when it really matters.