We've worn out a few paper shredders over the years, and I don't think I'll be buying another. Went to Home Depot (big box hardware store) and found a big terra cotta flower pot (about 20" high and 16" in diameter) and a couple of bricks. Cost was $20. What we have now is a nice looking high-walled fire pit that's practically designed for the purpose of burning papers you don't want people to steal info from. Some of these ornamental flower pots are much more expensive, like up to $60.
No need to use a lighter fluid or gasoline. You could use this for a barbecue if you had a grate.
Just set it up in the garden, put some papers in the pot and let them burn. When you're done, dump some garden dirt over the ashes and let it cool. Then bury the ashes later.
It adds a dimension of fun to the chore.
I have no plans to use it as a barbecue, but if I were to do so, I would first start a roaring charcoal fire in it to burn off any plastic or ink residue. I find that window envelopes burn quickly and the plastic doesn't contact the walls of the pot. Also, if you do this, don't get a glazed pot because the glaze might have lead or other toxins in it. Just use unglazed terra cotta (orange clay).
Works great, and it's really cheery. We make a little outing out of it, kind of like a fondue dinner but with fire instead of food. Everybody reaches into the trash box and picks up a piece of paper, then takes turns dropping them in the fire. On a cool, drizzly night we have enjoyed the warmth and the flame and the conversation.