here is how to make a quick mini ropedart pretty cheep (if you have the stuff laying around. otherwise it will cost about $5 US, with lots of leftover material)
first, get some braided mason's line like this:
mason's linethen get an eye screw like this:
eye screw (mine's about 1.5 inches long)
and cut a length (i use about 15 feet) of the cord, and tie it on to the eye screw with the best knot you can think of. i use a trucker's hitch:
trucker's hitchmakes for a good littl epocket version of the ropedart (though deploying it is a little tricky because the line likes to tangle when i take it out of my pocket. perhaps a loose monkey chain?)