No, youre totally off the hook here. No gifts are expected or given at Bachelorette parties. Normally, the bridal party or MOH will put together a night on the town, dinner, or whatever else for the bride. Since the purpose of this is to treat the bride to a night out ,the bridal party usually hosts and pays for the bride. So, if youre not a part of the bridal party, youre not expected to do anything at all.
As far as them having a Passion Party theme and having a Salesperson /consultant come over; this is why I dont really love these kinds of bachelorette parties. Because you are NOT obligated in any way to purchase anything; however; when someone invites you to a party where a product will be advertised to you at that party; you may leave there feeling guilty for not buying anything. This is why I usually dont go to most bachelor parties. I usually find them boring --- unless its something really different and fun and unique.
Point is - youre not obligated to do anything at all. Attend if you want to, but dont let yourself feel guilty for not buying product.