Bike accessories?

[kdsorceress.livejournal.com]

So, after three years living here for college and determining that I really do want to spend the rest of my life in this area, I've finally gotten my hands on a bike. Woo!

Trawling the bicycle tag in this community has given me some fantastic advice and things to keep in mind about the actual riding, but I have a simpler problem to handle first --namely, that I have a bicycle, and nothing else.

So, where's an affordable place to get a helmet, lock, and lights? I'm a broke college kid, so I'm not looking to spend too much money (though I've already been told by virtually everyone to spend the cash on a u-lock rather than cable), and I live out between Porter and Harvard, so shops on the Cambridge side of Davis are much more convenient to me.

Thanks in advance for the recommendations!

~Sor

(eeeeeee, bicycle, eee!)