Here is an example in Northern Utah. Right now there are 3 MK V 510's and one 520 for sale on the KSL TV classified web site. They all look very clean and in very good condition.
The first 510 is a 1995 date and the lister says it has never been used. It looks like that and comes with a band saw. $1250.00
The second 510 also has a band saw. Unknown vintage but it is a C head stock. $800.00
The third 510 is a 50th anniversary model with a band saw. $1800.00
The 520 is a 1992 date with no SPT's. He does have all the STP's for sale separately. $1400.00
That is a wide range of prices. However, one never knows what they actually sold for.
I bought locally a complete, never used as far as I can tell, stand alone over arm pin router with castors for about 1/3 of the original listing price. I paid $250.00
Eagle's Lair Woodshop