Less than you might think. It's not a trivial matter to get an .ie domain. The IEDR's rules make things difficult if you can't either (a) demonstrate a connection with Ireland the reviewer will accept or (b) demonstrate that you trade in the Irish market. There are ways around some of their rules, such as getting a registered business name from the CRO, but it really is a pain in the backside.

I write this as somebody who works for one of the biggest .ie registrars.

It's also notoriously painful to register a .ie domain. You need some connection to Ireland, but even if you do there are restrictions on what you can register (needing to have a company name or registered business name matching the domain, for example). They have loosened up considerably on the discretionary domains, but it still seems to take at least a week to get your registration approved and completed.