Holy cow. So I bought one these last week (26 Feb) just for grins. I thought what the heck, I can get my money back via paypal or ebay. Any the guy sends a link and an IMEI. But the link (same as OP) is one I've used before (since the Ipad plan was terminated) and it DID NOT show the 30 day unlimited option. So ripped him a new ahole and told him he was just a POS and any idiot can generate a fake IMEI. I didn't even try to make an account.
However, after reading this I decided to give it a try using the IMEI he provided and new SIM card. It freaking worked!
The option is there for the 30 day unlimited plan. I successfully set up the account.