I'm not exactly sure where you can find some free access passes, but I know where you can start looking; chat rooms. I found chat rooms that gave out 10 gem ourworld codes for free, I'm pretty sure you can find some sort of chat box or blog that gives this kind of stuff away. Start looking in Xat Chat Rooms. There's plenty of chat boxes there. Find one that has the word IMVU in it and you just might get a free access pass :P
I hope that helped!