Variety packs bundling three or four different strains are a sensible first buy if you have no idea what you like yet, since one grow shows you several plant types side by side. The downside is that different strains finish at different times, which complicates a single harvest. There is a beginner mix on https://budweedseeds.com that pairs strains with similar flowering windows to avoid exactly that problem. Once you know which type suits you, single strain packs make more sense.