I've used the Sena 3s for a passenger before and it was a great budget option. It's cheap and it worked great as a passenger intercom. It's currently on sale for $79 at Revzilla.

The downsides:

• The speakers are thick, you'll need a helmet with proper cutouts like a Shoei. The battery and electronics are crammed into the speakers.
• The range is only for rider to passenger, not bike-to-bike.
• The audio quality is fine for intercom, not great for music.
• No advanced features, just the basics.

I see negative reviews for it online, but it worked out fine for my use. My passenger has since upgraded to a Neotec with integrated comms.

 

Thanks! I'll have to look at this. It sounds like just what I need!

 

Get her the same helmet you have and I'll bet she will want to ride more than you think. With that said after 56 years of marriage and owning motorcycles since day one my wife hasn't ridden with me for the past 3 years.