One thing about working with paper and handpunchers is that you need to keep your blades in tip top shape, or you're going to be fighting with your puncher and cursing the day you decided to get into paper crafts.
Here's an easy way to keep your punches sharp, without having to spend $10 on every sheet of aluminum sharpening sheet.
Take tinfoil, fold it
Viola! sharpened blades!
Repeat as necessary, and you're welcome...you just saved money by using tinfoil that you already had! No fancy schmancy sharpening sheets needed!