http://www.forbes.com/business/2005/06/20/cx_de_batmanslide.html?thisSpeed=60000&boxes=custom So if you did not care about the billion-boy alter-ego, don't want a butler, already have combat training, don't want the car because it will make others suspicious, and do not need a cave to hide your gear, you can be Batman-esk *right now* for less then 2 thousand dollars a year at the most as far as Forbes is concerned.
I gave myself an hour today to try to disprove that idea, thinking that with a scientific frame of mind I could be less able to confirm what seemed possible. This is what I found:
There are sites out there that will do custom work to help you bullet proof any garment or suit you give them for about a thousand dollars per uniform by adding Kevlar panels and other modifications.
There are sites out there that will hook you up with all the spy gadgets you need cheaply, even if using them is full of legal restrictions at the federal level.
There are sites out there that will gladly sell you retractable batons, pepper spray, and electric shock devices for under $100 each for personal protection
There are sites out there that will gladly sell you the nitrates required to create smoke bombs, special effects and fireworks, flash-bang ninja powder, or even gloves that let you spit out fireballs from concealed projection arrays in the palm of the hand for only $20 - $80.
In fact, Amazon or even Walmart (Think 'Sports and Recreation') has some of these things at slightly cheaper prices.
I even found this in my hour of search time..
http://www.greatwhitesnark.com/2007/07/19/you-dont-have-to-be-rich-to-be-batman/ .. and it pretty much confirms the idea that being a Real Life Super Hero with all the Gear is pretty much in the grasps of anybody willing to save about $166-$250 a month for a year, then use every cent to gear up.
Or. you can just use a credit card and start today.