brands of SSD to buySamsung, Intel are the leaders. If the laptop that is the meaning of cheap, like kingston, adata.
Whether to focus on volume?Well, it's up to you. As you need a place for programs and data? It should be remembered that the eyeballs score SSD is impossible.
Whether to take the disks with the inscription PRO?In most cases it is just marketing, the focus should be on performance.