I'm a casual player that just got into Netrunner. I don't intend to play competitive but I'd like to collect every data pack and every expansion. Are there any of these data packs / expansions that are out of print or hard to find?

Well, the two cycles that are rotating out would be out of print? I doubt you will walk into a local game store and find every pack available, however it is possible to find them all online.

The rotation of the Genesis and Spin cycles is fairly new, so it should be rather easy to find them if you look several places. You will probably also find many people selling them nowadays. But I have to warn you that attempting a perfect complete collection is/can be a very tiring and expensive undertaking.