What I normally do is wash and chop the parsley (discarding stems, unless I freeze them for making stock later), put it in a ziptop bag, and stash it in the freezer. Works fine for cooked or garnishing applications but not for recipes that NEED really FRESH parsley (like tabbouleh or chimichurri). So convenient!
I do the same as Chowbird. It's easy to break off a chunk of the frozen parsley for however much you need. But I only use it for cooked applications, not fresh (not even garnishing). It is very easy to grow. You might want to consider growing some in a pot or in your garden so you can have it fresh all summer.