Here's an idea of the breakdown to get into airsoft:
These things are mandatory:
Decent starter AEG: $300
Ammo: $15 (2,000 rounds, should last 2-3 games depending on how much you shoot)
Eye Protection: $60-$100+. DO. NOT. CHEAP. OUT. HERE.
Footwear: $80-$120+. DO. NOT. CHEAP. OUT. HERE.
BDUs: $60-$100. If you're spending more than $100 on BDUs you're looking in the wrong place.
Hydration Solution: $30-$60. REQUIRED.
Good battery charger: $60. A cheap wall adapter is NOT a good charger.
Extra batteries: $30-$60. Always have at least one extra.
These things are optional, and not required for your first few games:
Tacvest: $80-$400+. You can get cheap vests, but they suck. IMO be prepared to spend at least $200 on a rig if you're buying new.
Pouches: $20-$40 each. Some vests come with pouches, some don't.
Magazines: $15-$60 each, depending on your gun. Hicaps suck. Be a man and get some standard or lowcaps. Enough for 300-600 rounds.
Knee Pads: $30. I actually played 6 years without them. Now that I have them, I have no idea how I did it.
Tacticool gun accessories: $0 - $100 billion dollars. You can trick your gun out with everything or nothing, completely optional here.
So basically, based on my simple list above:
$605 to $815
plus OPTIONAL costs:
$750 to $1,495 (I used $150 for tacticool).
So you're looking at anywhere from ~$600 to well over $1,000 to get started. These costs are COMPLETELY realistic, I'm not bullshitting you. Depending on what you can beg/borrow/steal/haggle you might be able to do it for $500-ish, but I think $600 is a more realistic number.
"Someone in a Prius tried to race me at a stop sign the other day. I couldn't believe it. I had him for the first 100 feet or so but I can only walk so fast."