There are many different types of laptops you can purchase. First look at what you want to use the laptop for. If its games, make sure your laptop has a high quality video card, sound card, and at least 4gb of ram. If you are looking to have this for work, make sure you have a decent harddrive capacity.
The two most important factors in buying a laptop is what you want to do with it and if it supports the OS you want to run on it. Laptops for gaming need a good graphics card, but standard usage only requires a good processor and a lot of RAM.
What do you want to do with it? Email, websurfing, microsoft word= 1-2GB ram, small hard drive, single core processor. Gaming, music-video editing, 3-4gb ram, big HD+ dual core processor.
The basic to look for are enough disk space, a fast enough cpu, and enough memory. A decent computer should have over a 100gb's of hard drive space, At least 2. 5 to 3ghz processor, and about 3gb's of ram depending on the operating system.
this is what i would do to buy a laptop. a apple macbook is a really nice laptop there fast and very easy to use they cost a bit more but there better in the long run
CPU,Memory,HD,VGA Card(usually takes memory from your RAM at onboard Cards). You can buy an external hard disk so priority to CPU and RAM. if you want to play games vga card too.