Clearance Sale at the Black Market - S4-E1
Continuity mistake: When Hogan is talking to Kiegel, Hogan's eyes are level as he looks across the table at Kiegel. After Kiegel says "Not good enough!", the camera cuts to a close up of Hogan, and he's now looking up as if the Major is standing. A moment later, the Major stands and leaves.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.