The value of an 18k gold bracelet depends on if it is plated or solid gold. The weight and percentage of the gold in the bracelet must be known to calculate the value. As of September 2014, the spot price for gold is approximately $1,200 per ounce.
how do you make hand-woven bracelets with yarn?
No. EXCEPT for a placebo effect ... which means it works even if you only think that there are magnets.