It does not promise the 6m per hour, nor are the items as easily buyable as you may think.
I've had the item in 6 of my slots for 12 hours now and it has not bought any of the item, and trust me you would need a LOT of this item to x-fer anything at all.
I suggest you guys find another x-fer guide to buy as this one clearly doesnt meet the requirements OP specified
I can easily get 7M / Hour using this guide, as for the items needed for the guide, they do buy in the grand exchange, I have used this guide to sell gold on multiple occasions, and actually have quite a high stock of the item(s) atm
Dragon Kid, you are wrong, it doesn't take anywhere near that long, I've been collecting for about 2 weeks, I have roughly 300M in supplies ready to be xferred.