And in the last 50 years, that appears to be Woody Williams, pitching for the Padres in Colorado, who was credited with a win despite a game score of 12. The game was played on April 7, 2001.
The Padres trailed the Rockies, behind Mike Hampton, 9-6, going into the sixth when the Padres scored five runs, the last three on a home run by Phil Nevin off of reliever John Wasdin. Williams had a double in the rally as the Padres took an 11-9 lead.
Williams came out to pitch the sixth and gave up a single to Neifi Perez and was relieved by Donaldo Mendez, who only allowed one run to score in the inning to cut the lead to 11-10.
The Padres won the game 14-10 with Trevor Hoffman picking up a one-out save when he came in to retire Ben Petrick with two runners on in the bottom of the ninth.
The higest game score for a losing pitcher in the last 50 years (and it's likely the highest ever) is, unsurprisingly, Harvey Haddix. He posted a 107 in his famous loss to the Braves on May 26, 1959.
The cheapest save, in my opinion, goes to Dave Goltz, who on June 6, 1973 pitching for the Twins in Cleveland, gave up 8 runs in 3 innings. Goltz gave up four home runs in the game, which the Twins won 13-9. 8 runs in the most runs any pitcher has given up since the save became an official statistic in 1969.