I used river rocks as tags for each of the dishes at the buffet table. The names are written with a white paint pen, which dried well. It was easy to write on the flatter rocks, but some (like the cheesecake one pictured here) were more textured and harder to work with.
It is possible to clean and reuse the stones with nail polish remover or paint thinner. I will probably end up using and reusing the same batch of rocks at future parties or events, adjusting the dish names as needed.
I also planted several herbs in old Trader Joe's coffee tins to use as a part of the centerpieces. I used a 5/8 inch drill bit to drill a few drainage holes in the bottom of each tin. The plastic lid fits tightly around the bottom of the tin to protect the table from any excess water or soil, though it should generally be kept loose or off so the plant does not become waterlogged.
Lastly, I gave away seed packets as party favors (apologies for the poor picture quality). I picked out several varieties of brightly colored flowers, wrote the bride and groom's names on a burlap tag, and tied a twine bow around the whole thing. I think ribbon may work better, but I didn't have any handy. The guests all loved them and enjoyed seeing what varieties their friends got as well.
All of these items were fairly inexpensive. I was able to save up coffee tins, and had scrounged river rocks from previous projects. The seed packets were less than $2 each. Together with a few other items, they created a great "garden party" atmosphere and the whole event was a huge success!