Cheapest form of transportation to get from Dublin to Manchester.
Great Britain is an island. What part of it are you shooting for? Probably Ryan Air. Check them.
We just want to get over so if by boat the closest city and if by air I am guessing Manchester. We will be traveling thru Scotland and England.
If you play their game, Ryan will be the cheapest way to do it. I've see their crews at Manchester, but that might not be the least expensive destination. They also serve Edinburgh and Glasgow. The cheapest/shortest ferry is going to be Dublin to Holyhead.