Hmmm... I have to admit, I'm a little suspicious of this one. It's one of those "party" money-making schemes, like Mary Kay or Pampered Chef, where you make your commissions by roping too-polite-to-decline friends into watching your frenzied product demonstrations and pity-buying some $30 moisturizer from you.
When you complete the survey for Park Lane jewelry parties, they'll send you a "free sample" of their jewelry. Now, it would make sense for them to send you something you could wear IF you were planning on signing up as one of their sales-bots, but for Sally Saver off the street? I'm guessing they'll send you one clip-on earring, so you can see (but not wear) the quality. But don't take my cynical word for it - maybe they'll send you something awesome.