Or, you can just save yourself $10 and use aluminum foil. It works just fine 99 percent of the time, and it's almost always in the kitchen. You just have to remember to get it out and use it.
I will say a pie crust shield is easy -- just pop it over the crust and you're good to go, but aluminum foil will mold nicely over elaborate crusts, which a pie shield may or may not do.
A pie shield is one of those things that is handy to have in the kitchen, and if you can find one on sale, to pick up. Otherwise aluminum foil is the cheapest thing out there and it's just as effective.