Hmmm, i just had a look for this on fleaBay, seems the Buy It Now price is up around the $2-300 mark, that's probably way too much for the quality you'd get. If you can get one for $50-60, that might be the limit of what i'd pay.

Still, for that price (even $150 or so) you can get a Jupiter 250mm f/3.5, two 2x teleconverters, and a PentaconSix to EF adapter for 1000mm f/14. It's obviously not the best, but I've taken shots of the moon using it (fills an aps-c frame), and the IQ was better than i'd imagine these Samyang things to be (of course, that combo ends up maybe 4-5kg and doesn't have a native tripod mount, but i hacked one together).