I started as a way to save money and make better beer than what I was drinking (Milwaukee's Beast Light). Granted, I loved good beer but wife wasn't going to let me spend $8/6-pack every few nights.
I became engrossed with the equipment and the DIY aspect of the hobby and pretty soon it became something I enjoyed spending my time doing, much like golf, fishing, movies, etc. But in the end I had fun AND created something that I would have bought anyways.
So imagine if you went to the liquor store and not only purchased beer but got free movie tickets too. Now you got beer and fun for the cost of beer.
So maybe the way to look at this is to compare a hobby that takes up the same amount of time as a batch of homebrewing does. Say, golf. 18 holes played at a wicked pace could be done in about the same time. What do you spend on the greens fees and cart and equipment costs?
If you golf less and brew more, I suppose you're spending money on a hobby, sure, and enjoying the same amount of time as you did when golfing...but you also get beer out of the deal.
I too have spent easily several hundred dollars and I'm only doing 5-gallon all-grain batches, have 3 cornies, picnic taps, no fancy kegerator, plastic ale pails for fermenters, no ferm chamber, etc. I spent money on kettles, FV's, heating elements/wiring, immersion chiller, thermometers, sanitizers/cleaners, ball valves/bulkheads, etc.
I went the cheap and DIY route on all of it, too. My 8g. kettles are aluminum and cost me $27 each plus shipping. My cooler I already had, bulkheads I did myself, hose-braid was DIY, chiller too, got kegs for average price of $40 shipped each, and a $40 CL fridge from the 70's. I think I've put about $500 into equipment.
I just did a bulk grain buy and I can say that will help tremendously. 50lbs. for $32 as opposed to $1.50/lb. from the LHBS (or $60/50lb. bag) is a huge savings. I also got a pound of hops for about $10 as opposed to $2/oz from LHBS ($22 savings). If you can get in on a bulk buy, harvest your yeast, and DIY as much as possible I think you can have fun building a brewery, making beer, and probably spending comparable amount on the product as you were before.
My last grain bill cost me about $7. Hops cost me about $1.50 and if you factor in the yeast had been split into 9 batches from one vial, that was just over $1. Probably $10 in consumables for over two cases of beer. Now i've made 13 batches or so...so my equipment cost is $38.50 per batch. Total for 2 cases of beer around $50. Eight 6-packs at $8 is $64. I'm still saving money.