FL Studio is available in 4 versions, priced according features. The most featured version, and of course, also the most expensive one is FL Studio Signature Bundle (at $299). The least one is FL Studio Fruity edition ($99).
We will try to guide you to your choice by asking you a couple of questions (and in the mean time, explaining you some of the concepts of FL Studio along we go).
Please realise that the more features you need/want, the more likely you end up with the FL Studio Signature edition which will cost you the most. So, please be aware that you can always upgrade later to a higher edition.
Ready to go?