I believe Duo is a scaled down version of Pro the prices are a bit sus though....pretty sure traktor is usually around $700 will wait for another member to confirm that
welcome dude dont worry, were good to noobs around here whats music do u listen to? and when your ready to get some gear make sure you post up in the beginners section if you have any questions or want recommendations etc
yeh that site is boss you can also make your own with audacity, but its very complicated and you have to have the original song and the instrumental version of it
easiest way would be single aux from laptop into your red n white's on your amp (if your using an amp) or if you have powered speakers then just go single aux out from laptop into master in on your mixer then just leave your speakers connected to your mixer how u normally would
yeh seems scammy as if your in melbourne ask to go to his house n have a demo on them before you buy, if he says no then just walk away cause he's probly some Nigerian WHALE