There are a few simple things to help reduce your budget.
First thing, check the Official EDR thread: http://www.bestdesti...-royale-thread/
I believe the lengths of sheers for the gazebo is listed there. The other option to reduce cost is just to do 2 sheers. If you look at most of the photos they have just two draped across the top, which the ends being attached to the corner pole. It is elegant, and classic.
As for the chairs, for the ceremony...it's only 15 minutes...on a beautiful beach! People/guests will likely be looking at you and the ocean, not whether there are chair bows. They set the seats up with white wooden folding chairs. (again view the official thread for photos) Perhaps do a small piece of decor on the chairs right on the aisle if you want some visual interest. But personally I don't think you need to invest in covers/bows for the ceremony.
For the chairs for your reception. If you are hosting a private event (ie. paying for dinner), please know that it is the same white wooden chairs, and they will have a simple white chair cover on them (this is included in the price).
Hope that helps.