My Dad used to carry one of those in his leather key case. They worked, were thin, and cheap. Not made anymore, but plenty available on Ebay, for 20 times the original price. But since a dollar's only worth a nickel, that's probably fair. Search "Bassett knife". After W.E. Bassett Co. was bought/merged with World Pacific Corp. in 2012, the Shelton, Connecticut plant was shut down, losing 200 jobs, and production went to China. Trim is still a World Pacific Corp brand, but they don't make the knives anymore.
Bassett made two versions, the Trim Trio, with blade, fingernail file, and combo cap lifter/slotted screwdriver, and a single blade version with combo cap lifter/short blade. The handles are about 2 5/16", with blades and tools 1 3/4". Sharpened edges about 1 3/8" and 1/2". I've seen copies by Liter USA and Korea. The nice thing about the Bassetts is that they stamped out a tab on the handle spine as sort of a backspring, and a cam on the spine of the blades/tools so they snapped into the fully open position. Poor man's slipjoint. The annoying thing about Bassett's sheepsfoot blades is that the tips are rounded past the sharpened edge, so there isn't a point at the tip. Safety feature, or just a result of the production process? I've thought about trying to make it into a Wharncliffe shape, but the nail notch is too close to the edge. Maybe sort of a lambsfoot profile? What do you think, Jack Black?
This thread needs more photos. I'll try to show the "backspring" and blade cam, and the rounded blade tip. The bottom tool is a Liter USA copy.