Hi there !
When you are looking to make rap beats on your own and you do not know where to begin it is not easy to find a software that will do everything for you.
I'm afraid to say that there's pretty much nothing like this... In fact, if you want to have something worthy, I mean something you can be proud of, you'll have to do yourself a favor and do it yourself!
All you have to do is learn the basics of music theory... You'll have to invest a lot of time in listening music, to understand how it is produced. Then you 'll have to buy a software like Protools, Logic Audio, Ableton Live or so... But in any case, if you want seriously make rap beats, a piece of software that cost 39.99$ will never help you.
All you'll have for your money are fancy dreams & the hope to be able to produce heavy Dr.Dre's beats for free.
Believe me, don't waste time looking for a software that will do everything for you and claim you can make rap beats as easy as 1,2,3 this doesn't exist.
Learn, practice, make mistakes, try again is the right path!