ah i did the maths myself to come up with $500.. you could have bought any ASUS wireless router.. I roughly guessed they should start found around $125 each.
ASUS 100% CASHBACK on Wireless Networking Purchase 4X PRIZES

2
Dates
Closing Date
30/09/2014
Draw Date
01/10/2014
Prizes
Description
100% cashback on a single Wireless Networking purchase from selected stores
No. of Prizes
4
Total Prize Pool
$500.00
Entry Requirements
Open To
Australia-wide
Entry Limit
Number of Purchases
Entry Methods
Facebook
Prerequisites
Purchase
To be eligible, consumers must complete the following:
Purchase any ASUS wireless networking products in selected dealers (online store or retail store).
Mwave Australia (NSW)
Scorptec Computers (VIC)
Computer Alliance (QLD)
Austin Computers (WA)
Upload the product photo and tell us why you like ASUS wireless networking products in the selected dealer Facebook.
Tag ASUS Australia page in the Facebook post.
There will be one winner selected from each retailer.
Something doesn't add up. The photo shows an Asus AC68U device, which costs $238.99 at MWAVE.
However, the contest details above state:
No. of Prizes 4
Total Prize Pool $ 500.00
4 * $238.99 = $955.96 > $500