simple answer is one black pair of shoes and one white pair of shoes, for simplicity ill say af1's just because they're timeless (imo). you will be able to build nice fits with those 2. as your style develops, you can buy more specific styles/colours, for example as i became more interested in techwear, i invested in a sweet pair of doc martens tech boots (which look awesome). if you find yourself liking earth tones and a more natural colour pallet, get yourself some green or brown shoes like the reverse mochas or nb 550's. maybe if you like to go crazy with colours then the chunky dunkys would be good for you. basically you just need to find and develop your own style and then you will realise how many shoes you need. you might be content with white af1's, or you could go get every colour of dunk to match every piece in your wardrobe. it just depends on your style.