I went to home depot and bought a infra red 250 watt bulb for about $6, i bought 2 just so i have a back up.
As for plastic, it works great this year however i went scavaging in my father in laws house he is ripping down and re building. I got some nice 60 year old roof joists and some siding from an old pool house and some 2x4 wall studs. I took some poultry wire and made a brooder 8x4, lamp at one end, put wood pellets on top of newspaper as flooring/bedding. This way the chicks can see out, meet the resident beagle without him towering above them and there is plenty of space for play and general chick tomfoolery!