Here's a tip for an inexpensive tiered wedding cake...
Buy two sheet cakes from Costco, ask for extra frosting and no colors. Buy a package or two of white chocolate chips. Take one of the cakes and cut it in half. One of those halves will be the second tier. Cut the remaining half, in half. Put one aside for your 1st anniversary and the remaining half will be the top tier. Melt the chocolate, once it's cooled, use a potato peeler to shave it. Use the heavy frosting to cover the cut sides. Press the shaved chocolate to the frosting until adequately covered. Get two boxes of varying heights and one pretty table cloth. Cover the boxes with the tablecloth and arrange the cakes. Buy some inexpensive cut flowers and a cute pair of S&P Shakers as a cake topper and arrange to your liking. Total cost will be about $40 - 45 (w/o the shakers).
I did this for a friend who eloped and she loved it. I wanted to get her a real wedding cake, but couldn't spring the minimum $100.00 (for a very small tiered cake) on top of everything else I had already spent.