You can do a lot without spending any money.
Ableton do a fully functional demo of Live 9 for 30 days - download that.
Fabfilter (excellent plugins) do a great demo too, for a couple of weeks for all their stuff - download those.
Native Instruments demos run for 30 minutes, then you just close and re open - download the Massive and Kontakt Player demos.
You’ll need some samples too, and you can get some high grade ones for free by heading over to Beatport and grabbing all the stems for all their remix contests. This is a brilliant way to get pro grade samples for free.
Loopmasters offer more free samples - they do tasters of their sample packs, raid all of those.
I came to production from DJing and eased into it slowly, first by doing some re-edits, then some basic remixes and mash ups, then into producing original tracks. Ableton’s great for working with all your free samples and loops, and as a DJ it should make sense to you. Collage all your free samples together into some tracks and see where it takes you.
If you have a mac, play around with GarageBand - again it’s not going to cost you anything and it kind of does everything you need! If GarageBand makes sense to you then just get Logic, you can’t argue with that price!
Once you decide to start paying for software, Massive really is indispensable and can create a huge variety of sounds. Sylenth is excellent too, great presets, which you need when you’re starting out.
Monitoring is super important, get to know your speakers, buy the best you can justify.
Lastly you’ll need lots of time. It’ll take years before you’re producing anything you would play out. Anyone who tells you they started building beats like a G is lying!