Consumables are always the biggest factor in anything, and the more you do it, the more you have incidental to that. Think about it. Say you go from shooting 1k a year to 10k (caliber doesn't really matter except as a factor of cost), but increasing by 10x is going to result in? 10x more cleaning (cleaning supplies); 10x more chances for parts breakage/wear (replacement parts); more need to go to bigger matches to justify the training that you have increased by 10x...which leads to more travel expenses, etc. All these things tend to magnify each others cost increases.
So how to keep costs down? Efficiency. I've finally convinced my wife that reloading is worth it by showing how many rounds I have to reload to make it worthwhile (she only sees the upfront cost of reloading equipment). I shoot on open ranges where it's free to shoot. I recycle stuff for targets (moving boxes, anyone?). I keep to minimum, common calibers and gauges.
I know I'm preaching to the largest choir ever, but just my two pennies. And blaster113, I agree. I told my wife that I could do this and have it be practical, or spend my life trying to be a golf pro....