Smart! I'm not sure where you are having the reception, but we had ours on the South Sky Terrace, and the area alone doesn't require much decoration at all, but we did bring some things, not necessarily to save money but just so we could have it be what we wanted.
We just used the free ivory table cloths provided by the resort, and then we brought larger squares of burlap to go on top of the table cloth. We rented glass vases from the decor company through the resort, and we asked them to fill them up with sand. We made and brought table numbers, mustaches and lips on sticks, so they put those in the sand-filled vases. The only other thing we had that provided a big pop of color was we brought larger wooden maracas that we used as seating cards. So whether you bring something or have a florist bring it in, I wouldn't worry about it at all! It'll look great!