Looks like a good deal if you are looking for one of this. Not sure how much credit is included and how long it will be valid for.
According to the Optus website details appears to be as follow:
http://www.optus.com.au/shop/prepaid/mobile-broadband/wifi/e…
3G compatible
This 3G WiFi modem kit comes with the 3G WiFi modem, allowing you to connect up to 10 devices to the internet at a time whilst on the go. Share your plans included value across your computer, tablet, mobile phone or game console - it's a great way for families who want the convenience of a home WiFi network combined with the portability of mobile broadband.
The 3G WiFi modem kit1 features:
Up to 2GB of included data^ with 14 days expiry for use within Australia
One touch connection
5 seconds fast boot
Support up to 10 WiFi-enabled devices connection at the same time
Support DC-HSPA+ data service up to 43.2 Mbps
Integrated Micro SD card slot, supporting up to 32GB
Free delivery for online order only
What's in the Box
Optus E5251 WiFi modem x 1
Rechargeable battery x 1
USB cable x 1
Power adapter x 1
Quick start guide x 1
Safety information x 1
3G = deal breaker…