Ilford Multigrade 500 head - how much $$$

How much would a clean but used Ilford Multigrade 500 head be worth in today's market? I've got a line on one with all the controllers, mixing boxes, etc. The rub is I'm going to need to buy it as a part of some other stuff which I don't need but can resell.

If you are planning to use it yourself be aware that the mixing boxes are often specific to each enlarger, so although you can usually make your own adapter to mount the head to any type of enlarger you may strike trouble with the mixing boxes being too long or short. The 4x5 box for the Beseler 45 is so long that it was split into two halves, otherwise it would be impossible to remove it from the head. If you are just enlarging 120 and 35mm there will be fewer problems like this to contend with.

saw one posted on craigslist for $400 over the past few weeks. didn't seem to be selling though.

Sounds about right - if it's complete and in working order.

Prices are all over the place on these (I've been keeping track - I've been looking for spare parts). A couple of years ago you could regularly find them for under $200 (There must have been a temporary glut as labs shut down and unloaded equipment). Lately they seem to be coming up for sale much less frequently and when they do the asking price seems to be in the $350-$500 range. Units w/ the proper boxes and adapters for some of the more esoteric enlargers can sell for considerably more (in the US it seems like the majority of the Ilford 500 units you see for sale are set up for Omega D enlargers).