Well, hey, a cheap set of SPD pedals are a nice thing- they're an unkillable pedal and will likely outlive you, if you toss them in your parts bin.
The problem with (nearly) all pedals is the cleats- at a shop, they have a ridiculous markup, and often cost almost as much as a whole new cheap pedal/cleat package online. SPD-sl/LOOK cleats are plastic and pretty easy to wear down, especially if you walk on asphalt.
Buying a new set of pedals (that will include the cleats) isn't a bad way to go when you're starting out.