Even though I thought this was always free, according to Appshopper it's been 4 years since it was free.
This was a pretty good version of Angry Birds, but I haven't played it in about 4 years.
Time to give it another go.
Non HD version is also now Free (was $1.49)
It's 35mb smaller than the HD version.
Thanks chadiwrx for pointing that out.
Was $4.49 (AU) if you want to update the title