Welcome. You and me both! And NYC too :). For the kids clothes and baby things, you should look for local yahoo and gmail family group lists. In my Nab in Queens, there is a family list serve with about 1,500 families on it and people are giving away baby clothes, toys, bikes, appliances you name it all the time. They also sell stuff for really cheap. Mostly, people want a way to free their small spaces and have their baby-kid stuff find a good second home. A little searching and you will find one in your community too I bet.
(I too am biking to work now -- 104 monthly metro pass will get reduced allot -- we should keep a NYC biker log to see how much we actually save by not getting the monthly pass since we may need to take mass transit still...)
two examples of cheap and free stuff from last couple days (you get the idea and there were allot more)
-- free air conditioner: kenmore model 58079053890 5100 btu
I tried to sort and inventory the bags as well as I could, but I was losing steam by the time I got to the third bag. Even though the bags are somewhat mixed with sizes, they contain clothes worn during the same time period. I.e., 2T and 3T leggings aren't too different in size. Everything is in very good to excellent condition. Anything not in good condition went in a "donate" bag instead. $20 each bag. Take 1, 2, or all.