This shop sells inflatable guards and monsters. The budget-conscious goblin chieftain, bandit queen or mad sorcerer will have some real minions, but give the appearance of having far more by using these cheap devices.
They are, obviously, more effective at night, and against animals. For animals who rely on their sense of smell, the buyer may 'dress' them in their real minions' dirty clothes.
If attacked the loud pop can act as an alarm, and at a slightly higher cost they may be filled with pestilent gas instead of air.
Although the owner does not say so, inflatable dragons (for example) may be used to terrify the gullible.