I bought this chain breaker from a local bike shop for $35(yeah I know). It works with the 415 chain and normal bike chains. Although it doesn't fit the 415 chain perfectly
, so when you re-attach a chain to itself the point where you reattached might be a little tight. Just grease it up and move it to let it loosen up a little. I haven't had a problem using this tool with the chain on my bike.
Park Tool Co. CT-7 : Screw Type Chain Tool : Chain
You can get them on ebay starting at $24.25 with free shipping. I know that seems a lot for a tool you'll hardly use, but it's good quality compared to the $4 Bull chain tools from Wall-Mart, and you'll be getting it cheaper on ebay than you would at an LBS. I don't know of any cheaper tool that will do the same thing. I've seen people on youtube use an awl and a hammer, but honestly I've tried that many times and I've never gotten that to work.