I've been carrying that Kershaw a lot lately because it has assisted opening, which I love.
That Spyderco only costs about $30 and is an incredible knife for the money. I don't like to spend a lot of money on my pocket knives because I'm going to work the hell out of them.
Those are just two brands, there are literally hundreds of pocket knife designs out there. Unless you accidentally purchase a foldable sword, I don't think you'll run into any legal problems with what pocket knife you buy.