It depends on the financial position of the company when it has served it use.
You can get the company struck off for around €1,000 or wound up as a Member Voluntary Liquidation for around 3 to 5k. However, these options to not apply of the company is insolvent. The MVL route can be a good way of saving taxes as any money left in the company can be distributed to the shareholders by way of a Capital Distribution and taxable as capital gains tax. The strike off route only applies if the company has no assets or liabilities. Because of the tax savings most companies go for the MVL route.
However, in the unfortunate event that the company is insolvent you are looking at a Creditors Voluntary Liquidation and this will cost you at least €8,000 but could be as high as €20,000 or even €200,000 if it is a substantial company with a lot of assets/issues for the liquidator to deal with. The MVL route is much cheaper because you will have dealth with most of the issues as a director before appointing a liquidator.