Weather-stripping is meant to close the gaps where things domove. It is perfect for doorways and windows as it is a taut material that is only attached to one side of the gap - for example only the door, not the floor - allowing the door to continue to sweep across the floor with ease.
One important thing to remember about sealing the leaks is getting the right product for the job. If you’re applying caulking on the exterior of your home, make sure to ask at the store for a type of caulking that can withstand the weather conditions where you live. The same goes for weather-stripping. There are various materials used for weather-stripping different areas of your home. Cost of weather-stripping will vary with the material, but you’re not likely to spend a lot, especially compared to what you could save on your energy bill.