The original box was ruined when the basement flooded.
I want to sell my 19 inch 19LG30 TV.
How best to package it?
Experienced Dopers are most helpful, but I’ll listen to anybody.
This might be shipping UPS.
Well, you could take it to the UPS Store and ask them to pack and ship it. But how much is a used 19" LCD TV worth? Will the packing and shipping represent a large fraction of the value?
Your local TV shop may well have a box they would give you. Failing that you need a bigger box and a lot of bubble wrap. Make sure that the box is totally filled and the contents held firmly.
Sell it for collection only or donate it to a local good cause.
I bet if I went to the recycling center to drop some stuff off I’d find a few tv boxes in with the cardboard.
Just what do you mean?
U-haul.
OK, I’ve decided to sell the thing at the Pawn shop, instead.
My thanks to you all. 
Well, if you’ve already decided.
Still, when I worked for Westinghouse Digital, we sometimes had to provide an RMA to someone who no longer had the box for his television (usually much larger than 19"). And we would send the customer an empty box with all the styrofoam inserts. A quick call to the manufacturer/distributor might yield a similar solution.
Cheapest place to find boxes is at a grocery store or other retailer. You can often go behind the store to the dumpster or ask someone that works there and get a few free boxes. Just have to find one of the right size for the TV. Then you’d fill it with packing peanuts.
But yeah, a 19" TV can’t be worth much.
Packing peanuts are not the solution when there is a single heavy object in the box. They will shift around and you’ll end up with one edge of the object leaning on the side of the box, or poking through it.
Or just re-use a suitably-sized box from the next thing you order online if you’re not in a hurry to sell. I’ve ordered things that have come in boxes big enough for a 19" TV even though you had to hunt through the packaging to find your item. I don’t sell anything online but if I did keeping the boxes would be prudent.
I know the OP has made his decision, but there is another alternative.