Do you have a kid? Does your kid like to swim? You need to get your kid some swim fins. We have two pairs, and every time we arrive at the pool I am immediately swarmed by neighborhood kids asking for a turn with our swim fins. They make you faster, they make you more bouyant, and to hear the girl children tell it very nearly turn you into a mermaid.
Here's the catch, to be the swim fin hero of the family/neighborhood pool, you are going to have to shell out a bit. The hard plastic ones found at my beloved Target are very likely to be a disappointment or outright rejected. Too flimsy, plus they hurt. We have two types, and my little wannabe Olympians have approved both.
First up, the TYR crossblade training fin. (TYR makes great goggles too, should you have a wannabe Olympian of your own.)
Our second recommendation are the Speedo rubber swim fins.
Both popular with my own kids and most of the neighborhood as well. Now, I've linked you to Amazon here, but my last bit of advice is to hit a swim supply store to buy your fins. Most swim stores will let you try the fins on in the bathtub (fresh water only please, once they hit chlorine they are no longer returnable) and then exchange for another size as needed. Since you are using them wet, the option to try them on wet is definitely worth actually driving to a store.
(Photo credit: amazon.com)