Not sure about brokers or website that use WAP/GPRS services, although your mobile network may be of some help...
I use Vodafone Pre-paid. When my credit runs out I can still use many of the features of GPRS for free, including checking stock prices.
Here is how I do it...
Find the extras feature of your phone, select Vodafone, then scoll down to find "The Buzz", then scroll down the menu to find shares. Type in the ASX code and you get a free SMS sent to your phone.
A word of caution: If you still have credit left on your phone you will be charged 50 per sms.
I can also access movie times, wheather, news etc all for free.
Naughty me, when I had no credit...I used to also download ring tones and wallpapers at $3 a pop for free, till some computer nerd found the hole in the system and they shut it down.
Damn Nerds...LOL Ohh well got stacks of free stuff for a while there
A tip for all electronic users is to find bugs/holes/floors in computer systems and exploit them till the companies find out and fix the problem, as long as it works in your favour!