Guys, lets not confuse things here. (
I've changed the thread title to be more accurate for other users)
Opera Mini is and always has been
free. It's a Java based web browser that uses Opera's Proxy servers to render the data. It is fast but limited.
Opera Mobile 8.6 for WM5 is the serious browser that costs money. It's probably one of the most robust browsers out there with tabs, etc.:
http://www.opera.com/products/mobile.../winmobileppc/
So this is just the old, free Mini version. Try it out, it's not bad, not great. It's certainly not as awesome as Opera Mobile 8.6 though.