Did you get anything from the mid year sale?  I got myself a cotton T-shirt for $5 to try out this stencil project.  I could not find freezer paper locally, but from the tutorials found online, I understand that it appears to be paper with a plastic coat. So the next best thing that came into my mind was the brown food wrapper with a thin plastic film that some hawkers still use to pack takeaways.  I use this all the time for my craft work.

And it worked!  I referred to these tutorials here, here and here.

A few pointers for myself to take note:
#1. Set iron on high (cotton setting) WITHOUT steam.
#2. Place a cardboard inside the T-shirt before painting to prevent color seeping through to the back of the T-shirt
#3. Let fabric/silkscreen paint dry completely before peeling off the stencil.
#4. Iron over the dried paint again to set it.

Have fun!