Not sure who your friends are? Listen for comments like "You've been a good friend to me" or "It's a fine day with you around." You can also check using the console, just select the NPC in question and enter: player.getrelationshiprank Be aware that not all favor quests result in an increase in your relationship with the person. You can use this mod to help fix some of those relationship oversights.
The same thing holds true of all other possessions; for barter, in general, had its original beginning in nature, some men having a surplus, others too little of what was necessary for them: hence it is evident, that the selling provisions for money is not according to the natural use of things; for they were obliged to use barter for those things which they wanted; but it is plain that barter could have no place in the first, that is to say, in family society; but must have begun when the number of those who composed the community was enlarged: for the first of these had all things in common; but when they came to be separated they were obliged to exchange with each other many different things which both parties wanted.
If you live in a major metropolitan area, chances are that you probably take public transportation to most of your destinations. You ditched your car long ago – eliminating parking, gas, and car insurance from your budget. But what if you need to get out of town for an hour-long meeting or pick up 25 bags of dirt from the landscaping store? Do you rent a car for the whole day even though you only need it for a few hours? Not if you have Zipcar nearby.