+1 on reading the stickies.
Bottling is cheap and easy. Start there.
I started off kegging, but I already had tap tower plans for my bar, so it made sense for me. If you have somewhere you want to put taps, and are willing to make the $$ commitment right away, I'd say go ahead and keg. But with that said, I still bottle some to take out of the house and share. So you'll wind up doing both.
Bottling:
Capper:
Wing Capper $15.00
Caps: Come with the kit = Free
Bottles: Beg friends, drink a lot of Sam Adams or some other pry-off beer = Free
Total = $15.00
Kegging:
Corny kegs: Craigslist, LHBS, Online = $25.00 + each (You'll need one, but you'll want more!)
CO2 tank:
5# = $80.00
Regulator:
Single pressure, dual gauge = $100.00
Connectors:
Quick Disconnects = $12.00
Serving:
Picnic Faucet = $13.00
Freezer: Craigslist, Online, Lowes, Home Depot, Sears, etc. = Free to $400+
Thermostat:
So you don't freeze your beer! = $60.00 +
Beer/CO2 line: =
$0.55/Ft give or take, depending on where you go to get it...
Total = $300 or more, plus the cost of a freezer/fridge/Or whatever you find to keep your beer cold!