Girls I need your help again!

My SIL contacted me a few days ago, bring up that since next yr shes going to be in college and joe being married, she wanted to do a dinner for IL's anniversary. DH and I are still a little tight, our car broke down this week, however its fixed. We agreed to take them to dinner at the chineses buffet I had my bridal shower at.
What I need is a low cost gift that isn't money or a gift card to give them. They pretty much have everything... so anything I give to them will be more of a novelty. We already gave them an album for our wedding, and we gave my father-in-law wine for fathers day. Any suggestions for a decent anniversary gift? My budget is very tight, I'd like to keep it at $20, we are willing to go as high as $40. I know thats bad, but with the car costing us $$$ and we are paying for dinner for five people, plus a cake.

Thanks girls!

What about a collage frame of your parents when they were dating/escorting one another to their engagement, to their wedding and their lives/

Or if you don't have photos going back that far, take photos of the two of them together throughout the years, along with pictures of you, your sister, your husbands, and any other impt family members.

We did that for the 50th anniversary for my grandparents and they kept it in their hallway until they died. It was always beautful to look at.