A good inexpensive macro lens?

Or an inexpensive lens allowing for some serious close-focusing abilities.

I don't expect to do a lot of this, so an expensive bonafide MACRO lens is not practical.  I had thought of maybe the 50 2.5 Compact Macro lens, but wondered if there were others.  Actually the 18-55mm kit lens allows for close focusing (if I recall), too.  I currently have only 2 lenses: Sigma 17-70 (the oder one), and a Canon 70-200 f4 IS USM lens.  Well, also a Rokinon 8mm fisheye, too.  But that won't work.

So what might you recommend?  Maybe no lens at all, but some macro accessories instead?  ie. tubes, or quality macro filters (like Canon 250 and 500?)?