There are a number of pajama sets currently available at SexyLocker which include pant and tee shirt style pajama sets. This allows for comfort when sleeping and warmth. Although you could simply bundle up in a thick sweatpants and sweatshirt suit, the bulk is not as comfortable, nor as attractive.
Try out one of the many pajama pant styles available at SexyLocker which are all made of breathable material that is comfortable and durable. The quality of all of the lingerie guarantees that the pieces will last and allow you to wear for a longer period of time than most products that are made in China and sold in discount stores such as Walmart. The pajamas at SexyLocker are just as inexpensive, but in the long run a much better buy for your money (and will keep you warm when it's cold out.)