First, I checked R4PG. I checked their homepage, and I didn't find any reference to "Entropia". So, either they don't sell it, and the OP got contacted by someone else claiming to be from them and selling obviously bad PEDs; or they sell it "under the counter" (they don't want to advertise in public that they are selling PEDs).
Secondly, their website seemed to be "hosted" by Cloudflare. Interestingly enough, some year ago there was a chinese website (Shanghai based company and website was also "hosted" by cloudflare) who hijacked accounts (avatars), TT:d all their items and then used the hijacked avatars to spam about their company. Their website reminded of this one. Though PEDs do have a fixed dollar value it was clear why PEDs were sold cheap: They (chinese website) didn't pay for the PEDs as they came from the avatars that they hijacked. (Obviously, they couldn't initiate a withdrawal as original avatar owner would notice that he missed items way before the withdrawal would had been completed...)
Edit: "R4PG is a Virtual currency trading company based in China." Another place it says "Beijing" though. A fake? facebook page claims it's supported by a sales manager at Alibaba. A thing that makes is fishy is there is no clue on webpage where it is (to, for instance, see which country's legislation that applies for purchases). The website has been involved in spamming forums (make sure your antivirus program is running... and google for "gteve22 banned"). For related websites google for UA-56284690 (Google Analytics).
There are two kinds of players who sell PEDs cheap: One type is those who want money fast. Or possibly want to withdraw a smaller amount than 1k ped, or can't receive international bank transfers. However, second type of PED sellers is those who have gotten it through for instance scamming, avatar hijacking or credit card fraud. And, well, the second type of PEDs sellers would of course don't tell that their PEDs are "illegal" and that the purchaser risks account lock. The second type of PED sellers just want easy money they can use IRL.