The fee charged by professionals for closing a limited company in Ireland is roughly €300 + VAT which includes the CRO fees as well as advertising in a national newspaper.
In order to close your limited company you need to apply for a voluntary strike off with the CRO. The CRO has a number of conditions which must be satisfied in order to close your company.
When the above have been completed it takes roughly 3 months for your company to be taken off the CRO register.
If you have a very simple business it is possible to do this yourself. If you have any doubts about how to complete the above steps it would be better to seek the advice of an accountant or a professional. If you complete any of the above steps incorrectly it could end up costing you a lot more in the long run.