Better off buying 500ft spools of construction line for $5/ea. A single strand holds 50lbs, won't rot or mildew, and is easily braided together to create a thicker and more durable line if necessary.The local garden center is selling one hundred foot lengths of 22 gauge wire on spools that are green in colour for $20 each.
They are very tough requiring a wire cutter to cut off smaller lengths. Simply flexing the wire back and forth takes too long to weaken the wire enough to break it.
I envision using this wire to aid in the construction of shelters, as a permanent trip wire, or on lashings that need to be resistant to moisture.