I use RadioOpt

its free and gives detailed information.

I'm using Onavo and 3G Watchdog at the moment. Both report results within 1-2 MB of each other. I prefer Onavo because it gives app break downs and will also give you alerts if background apps start using a lot of data. It can also notify you when you install apps if it is a known high data usage application.

I use RadioOpt

I think it's called Traffic Monitor, with the developer being RadioOpt :P

last edited by Twisted at 10:12:52 26/Apr/12

I have seen many people panic over this exact same issue with Telsta. In fact when I went onto my new contract I got an SMS from them saying I was over 90% of my usage and I had only used it for 2 days. I was thinking, how the hell did I just use 900MB?

Telstra often bring people into the middle of a billing cycle, and they set your data usage as a percentage of that cycle that has already elapsed. So there is a chance that you never actually used that amount.

I use one called Telstra Usage. It's good because it actually pulls all your data off the Telstra site so you can see accurately how much you've spent on calls and data.