You have the chicks already but don't have a heat source for them? Are you keeping them inside your home or in an unheated area like a garage or coop? In the nearterm,inside a heated home a regular 100 watt bulb may provide sufficient warmth.
check out your nearest farm store, they'll probably have what youll need. they say a 250w heat bulb (the red) one is what you'll need and then google the temp. requirements. i personally use a brooder plate (amazon) and will never go back to a lamp lol. and it also depends where you live. in hawaii so 10 chicks and a 60w lightbulb in a cardboard box is good enough lol