There are grants available for people living in social housing when going for central heating.The entire costs are paid by the gouvernment , but it could take a while to become first on the list . Hardship cases ( handicapped ect.) might have a chance to get an earlier appointment .
If you have a gas pipeline in front of your house than go for the natural gas , that would avoid the costs for a tank .
When going for LPG -you call it by the brand name "Calor " - then my advice is not to sign a contract for it. They will rent you the tank for cheap , about € 80 per year but you are not allowed to shop around for the gas. You would be hooked to the one supplier , be it Calor or Flogas or an other company.
Buy your tank. It costs not more than € 1000 .- including all costs like concrete slab ,placing/transport, VAT and commissioning and pipework to the house.That is once off . Every ten years it needs to be commissioned again ( pressure tested ) for around € 80 , some gas suppliers would do it for free. If you buy the gas from them . But keep in mind : No contract ! They give away the lamps for free and sell you the oil , as the saying goes.
LPG on the free market is around 20 % cheaper than from the contractor.The money you safe in 5-10 years by buing on the free market-depending on how much LPG you need-will pay for the tank .
Once you sign you are hooked . They can charge you everything and that is how they make profit . Tanks don't come for free , neither for Calor nor for Flogas . But they'll make you an offer that looks cheap to start with , "special discount" on the first 2 years /first two fillings .Rubbish. They'll take from you what they consider they need . The LPG market is not controlled , it's a free market , and you have to look after yourself . The cheapest LPG is available from TERVAS in Cork . About 20-30 % cheaper than Calor and Flogas .But they deliver only if you own the tank i.e. they won't fill up a tank that is rented from an other company .