surplusshed.com has some solid colored glass filters, at least yellow. Not sure about anything else. The large (100-120 mm) diameter ones are only in the US$3-5 range.

I don't know what his overseas shipping is, but he's more than fair for stateside, typically $5 for any order (I've never ordered massive items, but I think the catalog does state this).

Fred has an email contact on the surplusshed.com web site.

An occasional item he offers is in less than pristine mint condition, usually stated so, but I usually clarify with his whether 'perfect' is available or not. I bought his last front cell 12" Metrogon (who else would want half of a matched pair?). It turned out to be fungus etched, and he was perfectly willing to take it back, but I decided it was better to have than have not so I kept it...I found a complete mint set with filters down the road later anyway.