I HAVE attempted to make my own music, but just am not technically inclined enough to do so. I've used Fruity Loops Studio in the past which is a pretty robust music program. Shadow Dancer made their first album entirely in FL Studio (although its not dubstep):
As for samples, you can cut samples from other music. Daft Punk did this heavily on their Discovery album, almost every song had some sort of sampling from disco songs. You can also buy samples on sites like beatport if you're looking for something specific, they're a bit expensive and its probably best to just mess around with cutting them out of old tracks. If your interested in FL or sampling PM me and I'll try to tell you more, as I said I'm not very good with the program, but I've spent a lot of time in trying to learn it. lol
Also I'd recommend not going for any hardware while getting started as its pretty expensive. I'll also suggest trying out mixing songs with DJ software first, it may help you get a better feel on how to make electronic music. You can download the demo for Deckadance absolutely free, and its the entire program except they silence the player for a few seconds to prevent you from using the mixer in live shows.
As I said I have no musical expertise but I follow electronic music pretty closely. I've made a couple mixes with Deckadance in the past and if you are interested you can listen to them HERE. Or below: