avarin,

Welcome to my forum. It sounds like you might be looking for a guided bus tour of Ireland. With them you will know the costs up front. If you choose the right one your airfare, hotels, admissions, ground transportation, breakfast and most dinners will all be included in the price. You will have to pay for incidentals such as snacks, lunch, any dinners that are not included and tips.

I suggest you start by taking a look at CIE Tours and pricing them.  You can request a free tour guide at their website. They usually give a discount for booking well in advance. Some tours have senior discounts. 

That will give you a ballpark figure for a tour so that you can start saving.

Michele