Cost of Friendship

Sometimes (or all times) we have to literally "buy" friendship. It might sound improper or mean, but I think it partially depends on how you define buying. To me it could be both literal (like spending money) or somewhat indirect (sacrificing some of your time). I personally do not see much of difference between these two things, all they mean is you have to sacrifice something of value not generally not found free elsewhere. That's what the incentive of friendship is and that's what what keeps friendship alive.