In the 1972 Canadian federal election, the incumbent Liberal Party under Prime Minister Pierre Trudeau lost their majority, and slipped down to only 109 seats in the House of Commons (out of a total of 264 seats). The Progressive Conservative Party gained almost as many seats as the Liberals lost, winning 107 seats. (There were moments in the election-night counting and reporting when it looked like the PCs would also have 109 seats; but when the dust settled come morning, they only had 107.) The New Democratic Party under David Lewis won 31 seats, and the Social Credit Party won 15 seats. (There was one Independent winner, and one with No Affiliation.) Popular vote was 38.4%, 35.0%, 17.8%, and 7.6% respectively.

In the Canadian parliamentary system, technically, the incumbent Prime Minister is given first chance to form a government. However, if the incumbent governing party didn't get a plurality of seats, they usually don't bother. (There was one exception, in 1925.) In this case, the Liberals were the incumbent governing party and had the plurality, so they formed a government.

While they didn't engage in an "official" coalition with the centre-left NDP, there was an "informal" coalition which saw the NDP supporting the Liberals on many bills and policies. But when Liberal Finance Minister John Turner introduced the Liberal budget in 1974, the NDP wouldn't support it, the budget was defeated, that counts as an automatic vote of "no confidence" in the government, and that led to an election, in which the Liberals regained their majority.

Something similar has happened at other times in Canadian parliamentary history, such as between 1963 and 1968 when Prime Minister Lester B. Pearson's minority Liberal governments were propped up by Tommy Douglas's NDP. But the seat totals weren't as close in the 1963 and 1965 elections.

There's no record that I'm aware of as to any specific "inducements" or "bargains". However, the 1963-68 Pearson minorities famously introduced a number of programs which the NDP was behind, especially a national medicare program. (Tommy Douglas, as Premier of Saskatchewan representing the NDP's forerunner, the CCF, had gotten the ball rolling for medicare in Saskatchewan in the 1950s.) So obviously there was some quid pro quo behind the scenes.

Sources: Parliament of Canada website for 1972 election results.

Canadian Encyclopedia article on Minority Governments.

David Good, "Minority Government and Public Servants", Canadian Parliamentary Review, 2004, Vol. 27 no. 3.

(And lots in my head from just living through it, and studying it a lot, but not necessarily having my own personal bibliography re: where I got it all from.)