What are your barter items?

[Bobby]

Rightly or wrongly I can't stop myself thinking on the lines of barter items. I know being self employed probably makes me think on these terms, but hopefully once I've collected my essentials (food/water) making a profit (especially on those corporate b'ards) must be a good thing?
I've bought silver, gas, coal, batteries, toilet paper, sweets, booze etc and think come the big depression/ WW3 these will be a great investment. What would you buy? Is my thinking not in the Prepper spirit?