Tags similar to those Butch mentioned, though perhaps a bit 
smaller, are called Merchandise Tags. They are available at 
Wal-Mart, Staples and Office Depot, usually in lots of 100 
or more.

Of course, you can roll your own with some string, a hole 
punch, and a stack of 3 by 5 cards, old business cards, 
scraps of Braille paper, or card stock.

I have found that a good way to make Braille hold up better 
on labels made in this fashion is to first cover the card 
with a thin plastic "peal and stick" laminating sheet, also 
available at the above stores.

Back in the day, my mother, the secretary at work, or 
whoever I could draft, would cut old sound sheet magazines 
into sections, giving each a more or less straight edge so 
that the strips would roll into a Perkins more easily. I 
would ask them to do the cutting because I can't cut a 
straight line with scissors if my life depends on it.

I used those labels for various food containers, including 
those that went into the freezer. They would survive several 
cycles through the freezer as well as the dish washer if I 
forgot to remove them first.

I would also use this material to make labels for the tape 
cartridges that were in use in radio stations until 
everything moved to electronic storage.

I kept the 3M Scotch Tape factory in business labeling those 
tapes that way.

I haven't gone looking for them in a long time, but the 
above mentioned stores, or craft stores, may also have 
plastic sheets that would be thick enough to hold braille.