$1 charges on my credit card from iTunes.

I had six charges of $1 on my credit card to Apple NZ Gcs made on June 22. I had not purchased anything, apart from a free download of TomTom Go earlier in the month. I changed my credit card and my Apple ID, yet another $1 charge appeared on the new credit card to iTunes.Com/Bill on June 24. I reauthorised all devices connected to iTunes and wait to see if any more charges appear. I have no idea what I am paying for or being charged for.