The last time I bought anything like this it was the f/4 version in average condition and it cost somewhere around £80 I think. The relentless rise of mirorless cameras using adapted lenses and good old brexit mean that older MF lenses have gone up a fair bit since then so I would have to assume we'd be talking near or more than £200 for the 2.8 version. Greys have them for about £500 but their prices are generally, erm, optimistic. Do bear in mind that these AIS Micro lenses only get to 1:2 magnification. You'd need an extension tube to get 1:1. AF and AF-D and later AF-S lenses all fo 1:1 out the box.
To be honest, much as I love using these AIS lenses (they're generally beautifully made and very satisfying to use), much of the appeal used to come from how affordable they are vs modern lenses, but looking at this example, you could get a whole myriad of modern options from Nikon, Sigma, Tamron, Tokina etc for similar money, better magnification, auto foucs and probably some will be stabilised. Sure the AIS, lenses are pretty and nice to use but it's quite hard to justify the cost.
By the way, if it's not macro you're actually bothered about, take a look at the 105mm 2.5 AIS. That is a manual lens, I'd happily pay premium for.
