For shoes - they vary greatly per person - kind of like saddles on bikes.
I've run in Nike, Asics - and my last 4 pairs have been UnderArmour. I replace them after 500 miles.
Any good pair of shoes will usually run $70 - $100 dollars at a minimum.
My best investment was replacing the shoe's laces with the elastic laces with the clamp - $7ish on Amazon.
Once you get the tension right, you never have to adjust them again. Plus they slip on quick for T1 transition.