Hi, I've been driving my RX300 and noticing that when my front right tire runs over a bumpy terrain I hear a popping sound. If I drive over rocks I can really hear it. The car still drives very smooth still but I'm wondering if a ball joint has gone bad? I really don't know, can someone please help?

It is possible that it is the ball joint, however, the sway bar link tends to go bad on these vehicles also. You can look at either under the vehicle and see if the boost are busted or not.