This topic has come up a few times in the past, so if you search you will be rewarded
My pick of the entry level bugs is the Zebra. There the same price as the PL Comp-II/XR+ and in my opinion much better.
Second hand, well there are usually a steady trickle of PL Comp-II/XR+'s passing through the "For Sale" section, though I'm yet to see a Zebra rear it's head in there. If you do end up deciding to go for a PL buggy don't give the standard/ST any mind, make sure you get a Comp-II/XR+. It's doubt full anyone would try to sell you a PL ST but it's worth being aware they exist, even if it's just to make sure you steer well clear of them
So my advice, if you buying new defiantly consider getting the Zebra over the PL but if your after a second hand buggy I dare say you'll only be able to find PL bugs. If you do end up opting for a second hand buggy really, the Comp-II/XR+ is a fine bug.