Ocraknife, thanks for asking our advice.
I answer: Take enough money to buy two years worth of ammunition. One box of 50 each weekend (and allowing for missing a few outings makes 40 boxes or 2,000 rounds)
You could vey likely buy a press and that many bullets, primers and enough powder for them all. (If you are careful, you can get 10 firings out of each cartridge case.
for example. 2,000 bullets, 200 brass casings, 2,000 primers, 3 lbs of powder plus the cost of your hardware. You have maybe $1,000. That same $1,000 will buy those same 2,000 rounds over the counter. There's your break-even point (ignoring your own time). Don't shop for these figures, I just pulled them out of thin air.
Your mileage may vary. 500 S&W Magnums cost about $2.25 per round. Components are about $0.75. For 9mm or 45 ACP, it might hard to make a breakeven point. For .357 Mag, 44 Mag, 45 Colt, or almost any rifle round larger than .25 caliber it will be easy. Anyhow, there's your startup cost conquered.
3) Room to do it? My first setup fit in a footlocker. Mount the press on a 30" 2x6 strapped to an end table. Scale on the coffee table. Dropcloth on the carpet. 50 rounds an hour while ignoring the television. Easy, two hours once a week and I was all set.
4) I really enjoy having the independence of not wondering if my retailer will have ammunition for me. I especially enjoy being able to load bullets to whatever power level I like. My friend's 500 Smith is a pussycat firing 350 grain bullets at 800 fps.
If you waqnt to count your time into the mix, check out this thread.
http://www.thehighroad.org/showthread.php?t=663065
You are correct about learning more about your firearms. When you reload you pay attention to internal ballistics. The studying you do to work up loads pays benefits you can only try to imagine until you reload.
Lost Sheep