> After sending a bunch of these emails by hand, I wrote a Bash script for the process in my old Harvard Computer Society shell account (sending from a .edu address would make us seem reputable while not flush with cash). I tested it out, but having forgotten both “set -u” and to provide any inputs, it sent an email with all variables blank. The to: address defaulted to mailer-daemon@, an administrative list that all of my former HCS colleagues were on. They were pretty confused to see my email asking if I could buy “.com” from them, and I was suitably embarrassed. I figured the cost of further similar embarrassment would be higher than the manual time I'd save, so I kept sending emails manually.

> In total, I sent several hundred emails that day. Of the plausible responses I received, stripe.com was the clear winner. (Incidentally, I also got a reply from the parse.com owner; months later I sent my accumulated domain name list to Tikhon Bernstam, which is how Parse got its name.)

http://www.quora.com/How-did-Stripe-come-up-with-its-name/an...

Cost:

> We'd rather not disclose the amount, but it was less than you might think.

http://www.quora.com/How-much-did-Stripe-com-spend-on-their-...

Summary: They sent emails from a student email address to the domain contacts as listed in the Whois details. Cost was perhaps in the range of $2-20k (which I realize is a big range).