Start simple, get 3 spinnerbaits to begin with.
3/8 or 1/2 oz
clear/white skirt, tandem blades
white/chart skirt, tandem blades
chart or black skirt, single colorado blade
Also, pick up a pack of trailer hooks.
With these 3, you have the basics covered. Clear water, stained water, muddy water. I find the tandem blade combos the most versatile. But in those muddy water and night fishing situations, the colorado blade will come in handy.
For brands, I like Booyah, as well as some of the smaller custom mades, like Mini Me.
As far as retrieve goes...constant retrieve is the Devil's tool
Change it up. Burn it, slow roll it, bump it into stuff, run through the top of weeds, suddenly stop it, twitch it some while retrieving, etc. Keep changing things up until you find something that works.