It is not a sale price but it is the cheapest one you may find from the current market and it is in stock from Bunnings. (Was sold out before. Now is available from selected stores.)
Details:
1 Two Person Glider Swing
2 Single Swings
Height Adjustable Ropes
UV Stabilised
The 3 Swing Set includes adjustable ropes and plastic seats that will provide hours of enjoyment and comfort for your child and companion.
More details for how to assemble it: https://swingslideclimb.com.au/how-to/3-swing-set-3/
Get a good few bags of cement whilst at Bunnings. Each corner needs 2-3 bags.