Slaving over a hot Document

Slaving over a hot Document again this evening. However, a few minor steps forward today: forms obtained from the NatWest; first credit account set up; domain names registered.
I wanted to register four domain names. The most important one was available in both .com and .co.uk versions, no problem, but the secondary one that I wanted was available only in .co.uk form. I checked and found that the .com variant is being sat on by a domain name company, who, when approached, attached a price tag of US$3880.00, more than £2500, which is about one hundred times my budget for this. Is this utterly unreasonable, or what? Advice appreciated from anyone that has more experience of these things.
Incidentally, I wouldn’t be too concerned if I didn’t get this domain name. The one that counts is safely mine.