you can use silicon to block out light, it comes in a tube similar to toothpaste i saw it for $2.99, mylar will cut down on heat in your garden,it comes in rolls in the gardening section,both are available at home depot. you can dissect a computer tower to get fans to aerate your garden, rewire them to a dc plug its fairly simple, you can find lots about this stuff on the web especially on icmag.com. *PLEASE UPDATE PICS*
My man and i are in the same situation with cash and supplies, hope this help isn't too late to help.