Since I respond to threads like this about every month I will just quote myself:
Choose a music software, top programs are Ableton, Cubase, FL Studio, Reaper, Reason, Logic, and Pro Tools.
That will run you like $200~400 bucks though you can save money by torrenting if you want though I am a strong believer in buying my music programs. Also Reaper is only 60 bucks if you check my thread United Producer I have a Link to a free Ableton Lite 8 and bunch of freeware VSTs.
Then I suggest an Audio Interface which might run you about $100~500 though you can buy many used or in packages. *Side note* most Audio Interfaces come with light versions of the full program. Most have everything you will need to make killer beats and just as strong minus a few points.
You also may want good headphones or monitors. Again about $100 plus. I'd try buying these used as they appear frequently on ebay or amazon.
Last thing you may want is an midi control about $50 plus. You could actually get the Akai Mini which will have both pads and keys for $100 which is a pretty good deal.
So all in all if you take advantage of packages and such.
I'd buy a Focusrite Scarlett 2i2 inferface for $150 though you can usually use coupon to get down to like $135. I personally have it and only stand by Focusrite as they make the best preamps imo. Reason I choose the Focusrite for you it comes with Ableton Lite 8 saving you money on a software. And comes with 2 VST plugins a vintage compressor and vintage reverb both which are excellent. Also by having this form of Ableton Lite 8 you will have cheaper upgrades in future if you decide to stick with them. Avid Pro Tools also do packages like this but usually for $250+. Reason does one for about $450 with their Balance interface which does a new feature most interfaces don't do clip safe though if you don't plan to record still with Focusrite.
I suggest the Audio Technica ATH-M35 or KRK headphones as both are cheap and in great quality for mixing as they are flat which is what you want both can be purchased for around $50.
Now you can get an midi controller if you please. I did recommend Akai up top though I never use Akai because with a PC its a bitch to update your controller to work. I am a big Novation or M-Audio Person. With the $400 left you could get a nice controller such as the Axiom 49 2nd Gen or the New Novation Impulse. There are cheaper solutions that are just as good such as the KeyRig which is sold at Best Buy. It's made by M-Audio costs about $100. Features you would be missing are more faders, pads, and weighted keys I believe but it def gets the job done.
If you go with my cheap solution with the Focusrite package/Headphone/Keyrig you'd pay: $300
If you go better controller or software about: $500
Hope this helps
No need to torrent programs when almost every interface gives you the lite version of the program that does everything you need just missing their VST sets which usually aren't that good anyways. Check Here
or pm me I'll send you plenty of great VSTs that are equal or better than the ones you are torrenting for nothing. Side note: DAW I didn't mention but growing is Studio One which comes free when you get Presonus interface.