Hi fella, and welcome to RC...
On the subject of new or used... if you want to buy new, go for a well respected and popular (read common...) manufacturer for the availiability of trackside and RC shop spare parts... I think the B4 is a good investment new or used for anyone... The B4 chassis can take silly wind brushless and cope with it no prob if you want to, but are equally at home with more everyday wind motors... bear in mind that if you don't want to be a rolling roadblock for the regular racers, choose a motor/ESC accordingly.. ie. see what others at your track are using, not the top drivers, but the guys who will give you a race in the middle of the pack...
Above all else Heathy, have fun mate and try not to get caught up in the quest for speed through spending... consolidate your skills and respect the other drivers... there is nowt worse than a newbie with a fast car!!