For our 10th, my husband took me to Europe for 2 weeks. We went to England, Paris, and Germany. It was wonderful. For our 20th, He flew me back to Europe. On our 21st, he flew me in a private plane (he's a pilot) to Santa Fe as a surprise. He had made all the arrangements, to include a 5 star Spa/Resort and dinner. We only stayed overnight, but it was so romantic. This year we went back to Europe. LOL Honestly, we don't travel abroad that often, but we very much love it there. We lived there for a few years around the 15 year mark of our marriage.
I think it is wonderful to celebrate anniversaries, but I don't think you have to be extravagant if you can't afford it. Even a night in a local B&B or an evening picnic in the summer would be wonderful. You can order the food from a nice restaurant, add a bottle of wine and some candles (get a sturdy candelabra that won't tip over on the grass), with some romantic music on the ipod, and you have a wonderful evening planned! Enjoy your planning!
ETA: I just saw that you live in Miami. You can do an evening picnic any time of the year!!