It varies widely and you should check with your solicitor. As a ball-park figure, we have an arrangement with a solicitor in Co. Dublin who charges €1,000 all-in (i.e. inclusive of fee, VAT and all legal outlays). In my experience, that would be at the lower end of the range.
Don't be afraid to shop around but don't choose a solicitor on price alone. Ideally you should get a recommendation from someone you know personally who has used the solicitor before and was pleased with the service, efficiency etc.
Don't forget also that there are plenty of "free switch" deals out there where the lender will pick up the legal costs of switching.