I've been always servicing my car honda civic in official honda service center, but since I'm out of warranty recently, thinking to change it outside to save cost. A few question to ask almighty /k

1)I don't vroom vroom my car, what type of oil I need to buy? What brand? And how much?
2)Any good place to buy engine oil(Lazada/shopee?) or straight get from the workshop guy?
3)how much is the normal fee I have to pay?