Oh there can be many differences. There can be differences in performance and features. The cheapest cards often have such a single channel (for 2 drives), the somewhat more expensive ones can connect more drives. There also are cards with additional features such as RAID and JBOD. Cheap cards can have such features, but they often implement the real functionality in software (cheap but slow). The more expensive ones have dedicated hardware to do all kinds of RAID operations. This is way more expensive, but these cards are a lot better too (way faster, lower CPU usage, less OS dependent etc).
For your application, the cheap cards without RAID/JBOD functionality should be fine.