I use this code P382630. It from the Engineers Australia. Reduces the rates, esp. in Europe very nicely. Never been asked for proof even if I could.

Also, does anyone has experience what to do, in regards to membership levels, when moving around the world. I live on and off at different continents.
I was given Avis First, as I do have a US adress, but am not reachable there due to work overseas. Are the weekend coupons only good in the US??
And still, I can not enter the Avis First site, despite multiple emails and phonecalls. Any suggestions??