A programming laptop is an umbrella term of laptops that are fit for coding. This, unfortunately, is a very ambiguous term since there is one single type of laptop for programming. Unlike gaming laptops, manufacturers do not make dedicated laptops for programming.
If you want to play games, you go around looking for gaming machines. If you want to a business machine, you look for an Ultrabook. If you want to code, what kind of laptop do you buy?
In order to find a laptop, you first need to understand what kind of requirements you have. It is very important to realize what you need before you step into getting a laptop.
For example, if you are a student, then you will need the best laptop for programming student which would much cheaper than the rest.
If you are professional, then you will need to make a bit of investment. By professional, I mean someone who has programming as his/her career, not someone who can just program professionally.
If programming is your career, then you are definitely earning trough it. Therefore, it is important that you realize that having good tools of the trade in any business matters a lot.
So, if you are going to make an investment, you need to make sure that it is going to be a good one. A good investment in a laptop would mean that you would have high-end components like Intel Core i7 processor, a large amount of RAM and an SSD. I would 16 GB of RAM is quite decent for a professional programming laptop.
If you are into game development, then you need to invest in a machine that has a graphics card. A graphics card is needed for most development engines. This will put a quite a decent dent in your pocket, but it will be worth in the long run.