How to make 100 different NPC's

Let's say your larp consists of 20 players (on a good day). You have a budget of whatever you can scrape together. You have some basic skills, such as building weapons, simple sewing, basic construction... But with limited garb and resources how do you make varied NPC's? How do show the players what monster they face with verisimilitude and without expensive garb? How do you make that disposable hoard come to life? Here is one simple thing you can do to make 100's of NPC's, with the basic skills you already have.

Larp Viking Style Shield on a budget.

Taking an objective look at my armor, and thinking about where it can go, and what story it can tell, some viking additions seem in order. Although not watching Vikings on the History Channel, there may be some inspiration there. My current shield, although an awesome giant scarab beetle, really does not tell that story very well. Fortunately I found some inspiration for the new look.