Jay West wrote:
  Depends on what your definition is of affordable!! A
21MX E is cheap &
 common, I'd say they can easily be found sub $100. F's slightly less so,
 more like $150. M's are almost never found anymore, no telling what one
 would go for (but I'm about ready to find out). And have you seen what
 2100A or S machines go for? I've seen anywhere from $750 to $1500.
 2116's seem to go around $650 too. 
Well I have not seen any computers go for a song, since about 1982.
$300 seems like a fair price, with $300 for shipping for a basic less
popular vintage computer then.  I have the money ... Now who has the puter?
  Jay 
PS. For any deals in the UK, just think
'pound sign' instead of '$'.
 From here all shipping costs are about the same, other than Antarctica.