Originally Posted by European Lee

Dublin to Hollyhead by ferry = $30 (45 minutes)

Hollyhead to Gatwick by train = $100 (3 hours)

Gatwick to Amsterdam by plane = $30 (3 hours)

You might even be able to get that cheaper if (as already mentioned) you book in advance, you could probably even get a flight direct from Dublin > Amsterdam (or at least go through one flight change in Birmingham).

Regards,

Lee