a wild guess or ballpark estimate (The backronyms "Sophisticated Wild Ass Guess", "Stupid Wild Ass Guess", and "Scientific Wild Ass Guess" have been suggested for this meaning, but it is probably not the etymology.)
I can take a swag at the answer, but it may not be right.
a bushmans' possessions tied up in a blanket and carried over the shoulder on a long stick
handouts, freebies, or giveaways, such as those handed out at conventions. (The backronym "Stuff We All Get" has been suggested for this meaning, but it is probably not the etymology.)
A tramping bushman's luggage, rolled up either in canvas or in a blanket so as to form a long bundle, and carried on the back or over the shoulder; called also a bluey, or a drum
Luggage, knapsack, a bundle; also food carried about one Swag-shop, a store of minor, or cheap-priced goods (Scotch, sweg ) [Palliser] began to retrace the way by which he had fled and, descending carefully to the spot where he had thrown off his swag, found it as he had left it - Watson: The Web of the Spider chap v Swag Plenty Rhyming slang: A bag-full means plenty, and by omitting full, bag remains to rhyme with swag (See Chivy )
A carved relief or festoon in the form of a draped cloth hanging over two supports
handouts, freebies or giveaways, such as those handed out at conventions. (The backronym "Stuff We All Get" has been suggested for this meaning, but it is probably not the etymology.)"
n The stuff that manufacturers and vendors donate to be given away at bike related events When you race, go to bike shows, help put on events, write bike articles, you are often rewarded with swag Sometimes called "schwag"
A swag is a piece of material that is put above a window and hangs down in a decorative way
{i} decorative curtain or other hanging draped in a curve from two points; loot, stolen goods (Slang); swagman's pack or bundle containing personal belongings (Australian)
a wild guess or ballpark estimate (The backronyms "Stupid Wild Ass Guess" and "Scientific Wild Ass Guess" have been suggested for this meaning, but it is probably not the etymology but rather a backronym.)"