Welcome to the board, readinglady10!

The only special coins are the Circular 50c coins which are worth about $6 each these days. The regular 12 sided ones are all still worth 50c, mostly, but check out completed listings to see what might have collectable value.

There's a rare $1 coin out there with the wrong strike on the front  - I think the die should have been for a 10c piece. Basically it looks too small with a broader rim than normal. The back has a mob of kangaroos. There are millions of kangaroo coins out there, all perfectly normal, so your chances of having a special one are pretty small.

enjoy your trip!