What do you want to use them for?
Speedlights are great, they weigh little and are small and the softbox above is a great bit of kit (with some limitations).
But what do you want to do with 3 of them? Are you thinking of ganging them for power? or are you looking at complicated lighting setups?
If it's the former, buy a Godox Wistro / Lencarta Atom. They're about the same price as 3 cheap speedlights but much better. If you're after overpowering the sun, you'll probably want to get a Safari kit (one light will do a lot).
If it's for the latter, get one good light and learn to use it. If you're not going outside, buy a Smartflash kit (ask for more details).
The Speedlighters Handbook is a great starting point, as is the Strobist blog.