In California, you can rent a kayak for the day all over the place, and they'll give you a little instruction. After you get into it a little, they're not very expensive depending if you want a sea kayak or a shorter river. I couldn't make up my mind, and didn't have enough money for both, so I bought a decent hybrid for $650. Just cruise around the internet and look for places to go kayaking and you'll find people that will tell you the best places to go and such.