63d2328e_rication___Australian_Robotics__Sources
[Description] Ferric Chloride Etchant [3] Ultrakeet [Sources] 
Good old FeCl Etchant. I can't go past it for the speed at which it can etch boards using the method in this article. Its also the most reliable for use with Toner Transfer to ensure a good etch with no undercutting etc. Whilst harder to get in liquid form from stores these days - you can still get it through electronics supply houses in a powder form you add water to, such as digi-key or mouser. Ultrakeet are also a good online supplier through which you can get some.
PC to PCB in under 30 minutes - Quick 'n Easy PCB Fabrication | Australian Robotics
Sources