Depends really, I assume you are going to be doing cdjs or a controller?
I don't know fuck all about controllers, but they are a good starting point and an all in one system and are the cheapest option to get started. You can use USB or laptop with software so it's easy to keep your library on hand and sorted and you don't have to lug around bags of discs or vinyl and won't have crates taking up a lot of space in your house.
Most of my experience is in vinyl as I see cdjs as dirty, but you can't go wrong with starting off on some pioneer cdj 350s, basic as with no cue points, but a really good introduction, especially the bpm display which you will heavily rely on at first to beat match. There's also a beat grid display. These will do you good until you get some mid range 850s or the top line 2000 Nexus.
Mixer is more open, pioneer do a djm350 which is basic but has some inbuilt effects which will be a good intro to interesting mixes. Has a mic input too.
Although I haven't mixed on one I hear numark do some good entry level mixers too.
I would learn on a mixer before you go getting into using software like Serato or rekordbox.
Feel free to pm me any questions you have.
This post was edited by SenorNZ on Jun 21 2018 06:29am