Would people be willing to buy these?

I'd say "yes, they would".

Price would be dependent on costs.  What is the cost of the raw materials, and how much of your life goes into each one?  If your time is worth $20 an hour, and these take 30 minutes to make, add $10 to the cost of the materials.

Colours: depends on market.  If you call them "survival" bracelets, and aim at wannabe military types (the type who shout hut hut hut when they play paintball, and wear a lot of camo), then you make them in shades of brown and green to fade into the background.

If you call them "walkers' emergency bracelets" (or "hikers" or "campers"), then make them in neon colours so that they can be spotted standing out from the background.

Where to sell them?

I would try ebay first.  Make ten in camo colours, call them survival bracelets.  made ten in neon colours, call them emergency bracelets, and see which sell quickest, for the most.

After that, either stay on ebay, go the etsy route, try selling them to suitable stores, or take an ad out in an out-doors type magazine.

i got one for my birthday, by company called 'survival straps' my brother paid something like $20 for it, only difference and advantage i could see is that it's made with one piece of cord. But anyway good work definately start selling them! 

Look out for craft fairs, you could probably do well selling them at them...

i bet you could sell them $6.99 in red+black,neon green+neon orange,purple+yellow