If you are gonna be serious about spearfishing get some decent stuff out the gate. The following gear will last you forever, and you will not need to ever upgrade it (other than shafts and bands).
* 60-90cm euro speargun (Cressi, Omer, Rob Allen, Mako, etc) I prefer a 75cm for most of my diving.
* Longblade freediving fins
* weight belt (rubber ones are nicest for freediving)
* Black mask that fits your face perfectly (try them on if you can!)
I say support your local dive shop if they carry freediving stuff. If not you can order online.