I guess it really depends on what you want. If you are the anal retentive type that wants them with a 1/4" clearance on all sides, light tabs in this exact spot, and that they match perfectly with your current, proposed, and future modifications, you should build them yourself. Make them exactly right, just the way you want.
Also, if you are too poor to pay attention you might be able to save a few bucks fabbing them up yourself. This basically exchanges your time, for the time it would cost you to pay someone to fab them for you.
On the other hand, if you are okay with the pictures you've seen on the net, don't want or need anything special, and are okay with someone else's idea of a good design, for less than two hundred bucks, you'd be hard pressed to find a better deal. Plus, you get his tries and failures (design research) for free.