You need one diamond two-sided plate, holder for it, and a stropping leather. All of that can be bought for $60 on Amazon. This is enough to get your knives to

You need one diamond two-sided plate, holder for it, and a stropping leather. All of that can be bought for $60 on Amazon. This is enough to get your knives to be sharp enough to shave hair. Time investment is more individual. It took me about 3 hours to get good enough.