I have been useing my Pandora for mostly web searching, but I have tried once or twice with emulaters. I know there is a wealth of info on the Pandora help pages, but dont want to anything right to do right now as I could easily mess up the unit. I was wondering about one of the above units or any others that since they dont cost as much, one of them would be best suitable to practice on. Any help will be greatly appreciated.
You don't have to worry about spending money on a "practice" unit. The way the other units work, will not work on the Pandora anyway, as the Pandora is unique.
You assumption that the Pandora is easy to mess up is incorrect however. Simply download the .pnd files from any
software repository that you wish to install, plop them onto the SD card and poof they appear in your menu. For Emulators, the Pandora wiki is pretty clear as to where to put the BIOS or ROM files you wish to play. If you make a mistake and plop files in the wrong place, just, move them to another place and try again. Or not, either way, no fail. Worst case scenario, you make a huge mistake and totally trash the system, which is NOT likely to happen, simply download a firmware pnd, plop it on the SD, and run it. Or, if the Pandora wont boot, which means you somehow altered the files on the NAND itself, again NOT likely, just follow the directions on the wiki for reformatting the NAND.
Really though, there's little to be afraid of. Unless you are doing in depth tweakery, like custom operating systems or changing filesystem types or something, it is rather unlikely you will mess anything up badly. Experimentation is fun! And no amount of messing up can completely brick the system, its designed to be unbrickable. Except for physically abusing it, of course.
If you do plan on doing some muckery with the OS and are thus afraid of a broken install, you can look into the Boot from SD links on the wiki, it's no longer very hard to set up the Pandora to boot it's normal OS from the SD card. That way, even if you commit total fuckery upon the operating system, simply reboot without the SD inserted, and BAM it works perfect again.