Fine Gael topped the list of political parties in spending for the 2016 general election - including over a quarter of a million spent on 'market research'.
The party sank almost €2.8 million into its 2016 campaign, including €252,000 in research that partly led to its ill-fated and poorly received campaign to 'Keep the Recovery Going'.
The details are contained in the latest report from the Standards in Public Office Commission, which regulates political donations and enforces candidates' spending limits.
Fine Gael's campaign was by far the most expensive, with the second-biggest spend coming from Fianna Fáil, which spent €1.69 million - over a million euro less, in a campaign that won 44 seats compared to FG's 49.
Overall, spending in the 2016 election campaign came to €8.4 million - around 10% lower than the previous campaign in 2011.
Labour spent nearly €1.1 million on its campaign, which won just seven seats, while Sinn Féin's campaign to win 23 seats cost around €650,000.
Among the smaller parties and groupings, it is evident that some parties got better value for money than others in their campaigns.
The Anti-Austerity Alliance-People Before Profit won six seats in a campaign that cost €267,000 - compared to Renua, who spent slightly more (€286,000) but won no seats at all.
The Social Democrats spent €190,000 and the Green Party €167,000 on campaigns that won two seats each.
The Independent Alliance, which is not a registered party, did register centrally as a 'third party' group to campaign in the election - but centrally spent just €552 on its campaign to win six seats.
The Pro-Life Campaign also registered as a third party, and recorded over €40,000 in election campaigning - half of it for print advertising in certain local newspapers, but also with over €6,000 spent on Facebook ads, and almost €2,000 for pre-roll advertisements on YouTube.