A Solicitor will charge you a percentage of the deceased person's estate and could take ages.
When my husband died suddenly without leaving a will I did the probate stuff myself by a applying for a personal grant of administration. The staff in the Probate Office were very helpful and I think I paid approx €350. The fee depends on the value of the deceased person's estate but is much cheaper and faster than using a solicitor. The link below sets out the scale of fees. They've probably gone up a bit since then but it's still definitely cheaper and faster than using a solicitor. One solicitor quoted me a fee of €10,000 !!!! I figured that this money was better spent on our kids than line the pockets of a solicitor
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By the way the Oasis link above gives the old address for the Probate Office in Dublin. It's now located in Smithfield, near Chief O'Neills Hotel.
Hope this helps