NOW is the time to shop for light strands, also known as Christmas lights and twinkle lights. They're all at least half-off right now. It would cost us $1 a foot to rent them and our tent would require at least 200 feet. So last week I went hunting and purchased our lights at half-off retail, a total cost of $66. Two days later I returned them all because I scored an even better deal at a thrift store where all Christmas items were 75% off.
I managed to collect more than twice the amount we needed, 440 feet, for just $5.50. Go to thrift stores right after Christmas for lights. Just make sure you test them before purchasing to make sure they work.