If I where you, I would have my son shoot in the trap league for a month or so, and by then you will have a good idea of how much your son likes it. You can get set up with a Lee Loader II for about $40-50, a bag of once fired hulls (which I am sure you will have plenty of once you have shot a few boxes) for about $10 or so and then you will need wads and primers, powder and shot. I would say to get properly set up to load a couple of hundred shells you will be invested about $150-$200. That is the equivalent of 600-800 shells bought at Wallmart at the $23 per 100 your quoted. Loading shotshells is not hard, imho it is easier to do than loading metallic cartridges. If you are going to be loading a lot, and you know that you are going to be in it for the long haul then investing in an MEC loader would be well worth it. But the Lee would allow you to get started with a minimal investment, and it loads shells just fine, but not as fast as a MEC loader will.