where can I buy nameservers

[Pflege]

I hope this question is not off-topic:

Where is a buy 2 nameservers at a reasonable price for domains
that will be just parked by clients?
Currently I am using the parking feature at pair.com to park
domains - pricing is $US 10.00 per domain. This is reasonable, for
longer parking, but not if a clients wants to register and just get
parked the domain for a few week before building its own web site.

Is there a list of resellers offering nameservers?
(just for parking with 'under constuction')

Thank you in advance

Matthias