I have been seeing this question a lot on here. .. I am not complaining just saying this is a common question. However I feel this changes from area to area. 5K puts you in the clean area for a knee mill? shit you can buy a new import for that price. I think the 2K is a better price. But here in my area now that a ton of industry has left Cleveland knee mills are pretty easy to find. My 2nd Bridgeport here is a 2 HP Vari drive with Taper quick change, DOR, Spacer, super clean, and LOTS of ericson tooling. I picked it up for $1700.00 However there was no vice on the table.
It falls in more of a supply and demand issue. Is there a lot of machines in your area to pick from? Are you stuck having to buy from a dealer or can you buy it from a person?
Next question is now that you talked your boss in to spending X amount on your two machines hows he going to react when you tell him .. Oh yea I need triple what you just spent for the machines to tool them and will need more money for that as well over time? Keep in mind Machines are CHEAP its the tooling that cost the money! You pick up a mill with some tooling and a vice, First job you need a 2nd vice, and some tooling that did not with it. Then the next job you need a Rot O table .... the list goes on.
If you think your spending too much on having stuff machined maybe look for another shop? You might find you are already getting a good deal or you might find a better place?
Just my thought.