Here's what you'll need:

Empty pop cans.
1" X 3" Avery labels, or whatever size or brand you like.
Scissors.
Hole punch.
20 gage wire.
Ballpoint pen.

Poke a hole near the top of the can and cut the top off.
Cut down the side and then around the bottom.
These cuts will probably be pretty jagged so cut around the piece to smooth the edges.
Grab each end of the piece and run it over the edge of a table to flatten out the can. I wouldn't do this on your heirloom coffee table but perhaps a rounded counter edge.
Put an adhesive backed label on the painted side of the can.
Use it as a guide and cut around the label.
Punch a hole in one corner of the label. You may want to use a nail rather than risk damaging your good hole punch but a hole punch does work good.
Place the label on a soft surface like a mouse pad with the metal side up.
Using the ballpoint pen write your plant name on the label. You will want to press hard enough to emboss the label.
All that's left is to run a wire through the hole and attach it to your plant.

Make a bunch of these tags unmarked for a thoughtful gift.