In a post collapse situation, having items stored in surplus for bartering is an essential part of prepping. However, you can only stock up on so much of any consumable item and your supplies will eventually run out, thus liberating you of your bargaining power.
Enter renewable bartering...the use of renewable items and skills that can be traded for what you need that others have. Here is a list, albeit incomplete, of the top renewables that you can produce for bartering.
Alcohol & Tobacco - brewing beer and fermenting wine is legal for personal use, so you can perfect your skills now with no worries. Of course, learning at least the theory behind distillation would be a great idea, as distilled alcohol can be used for fuel, disinfection, and yes, drinking. Keep in mind that the distillation of alcohol IS NOT LEGAL in Canada, however, in a situation where law enforcement has gone the way of the dinosaur, this could be a useful skill to have. In addition, you could also offer some homemade lamps and stoves made from scavenged materials.
- Growing tobacco is legal, believe it or not with a few restrictions on quantity. Learning to grow tobacco is about as easy as tomatoes, so go ahead and give it a try. There are some details to learn in regards to drying it, but now is the time to figure that out. Seeds can be had online for around $5.00 per hundred. You may also want to try carving some smoking pipes, as rolling papers are likely to be in limited supply.
Keep in mind though, that people who have not been able to feed addictions for any given amount of time can become unpredictable. If you plan to barter with other preppers that you have known for some time, you should be OK. However, trading addictive substances with people that you don't know well can have implications and attract unwanted personalities.
Food - keep the use of food for bartering to a food for food trade. Perhaps you are quite proficient at growing tomatoes, but just don't have the space for wheat. Setting up this sort of produce for produce trade system now will let you get to know your bartering partners as well as strengthen community relations, which will be of utmost importance when all hell breaks loose.
Energy - Becoming the local power company in a SHTF scenario would be invaluable. No, you don't have to set up a huge power generation system and distribution lines to all your neighbors. A simple alternative energy system comprised of solar panels, wind turbine, micro hydro, or even a bicycle turning an alternator would give you the ability to recharge batteries. Of course, there is some cost layout to this, but many preppers are already looking into ways of producing at least some power for themselves. A little extra now could put you in a great bargaining place later.
Skills - This is probably the most renewable thing you can have. Once aquired, you can give it away without fear of ever running out. Learning how to do some home repairs, carving, basket weaving, or what have you, can not only be rewarding now, but very valuable post poop.
Labour - The saying that time is money is one of my least favorite expressions. Time is the one thing that is given to us free of charge every day that the sun rises. Being in shape to offer physical labor will be of great value to those that simply can't do physically demanding work.