$129 at Optus. If you want to unlock it you can try contact Bagman https://www.ozbargain.com.au/user/56629
You have to search if it available at your nearby store because a lot of store already out of stock.
http://www.optus.com.au/shop/prepaid/mobile/huawei/ascend-g5…
| Huawei Ascend G510 | Specifications | 
|---|---|
| Descriptive Colour | Black | 
| Service Provider | Optus | 
| Networking Connectivity Technology | Wireless | 
| Wireless Protocol | Bluetooth | 
| Technology Type | Touch | 
| Packaged Quantity | 1 | 
| Colour | Black | 
| Brand | Optus | 
| Internal Memory | 4 GB | 
| Clock Speed | 1.2 GHz | 
| Service Provider | Optus | 
| Mobile Broadband Generation | 3G | 
| Supported Flash Memory Cards | Micro SD | 
| Primary Camera Image Quality | 5 Megapixel | 
| Diagonal Size | 4.5" | 
| Band | Dual Broadband | 
| Phone Type | Android | 
| Operating System | Android 4.1 | 
| Number of Processor Cores | Dual-core | 
Y210 http://www.officeworks.com.au/shop/officeworks/optus-huawei-…


vaya uses the optus network, so this should work for vaya right?