There's a discussion in rec.backcountry about the cheapest way to backpack. Here are excerpts:
http://groups.google.com/groups?hl=en&threadm=VcnK7.21%24px5.9467%40newsfeed.slurp.net&prev=/groups%3Fq%3Drec.backcountry%26hl%3Den
Backpack: CamTrails Scout model $40.00
empty water bottle/pop bottles 0.00
Waterproof tarp from Walmart 9.00
Nylon Rope 3.00
Walmart Mess kit 7.00
MiniMagLight 9.00
Boots (Nike lightweight from CampMor) 29.00
Bic lighter 1.00
Total $98.00
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Trail Gear
Backpack Duffel bag (handle is shoulder strap)
Hiking staff Bamboo shoot or found stick
Canteen Used Gatorade bottle
Bedroom
Tent Mattress plastic moving cover (bivy sack)
Sleeping bag Blanket
Air mattress Bubble wrap
Tarp Visqueen
Rope Rope
Kitchen
Stove Coffee can hobo stove
Pot Aluminum model, from Salvation Army store
Mug Plastic coffee mug
Bowl Glad plastic bowl
Flatware Plastic from McDonald's
Water purification Coffee filters and Clorox bleach
Bathroom
Toothbrush From home
Toilet paper From home
Utilities
Candle Candle
Flashlight $2.00 drugstore model
Fire Matches or Bic lighter
Water storage 32 oz. plastic softdrink bottle
Clothing
Boots Tennis shoes
Rain shell top 39 gal. garbage bag
Shorts Swimsuit
Shirt T-shirt
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You could always go as John Muir did...go read some of his writings. If memory serves, he took the clothes he wore, a tea kettle, a blanket, some tea and bread, and matches. I recall one description where he brushed away the ashes of his fire and lay on the warmed ground. Talk about minimalist packing!