The arch came from a party store in FWB.

Here's where I got the arch:
Parties & Balloons By Yours Truly
348 N. Eglin Pkwy.
FWB, FL 32547
Phone: 850-862-4211

I think the cost was $75.00 I took the sand dollars that I bought from Sea Shell City on Highway 98 in Navarre, Fl to them so they could put them on the arch. They'll use anything you want them to.

My arch. Click for larger image.
 
I saw this arch at a mock wedding. The arch was provided by BeachsideBride.com
Click for larger image.

 
Usually it's too windy to have a unity candle on the beach. So instead we used a glass heart(bought from Walmart) and poured sand in it together. My aunt used glass paint to write on the glass.

 
Ideas:
Instead of a flower girl you could have a shell girl. Not recommended if you walk down the aisle barefoot.

Here's a few ideas for an aisle: Use hanging plants, flowers or tiki torches. I used chairs to create a walkway.