If you read the seller's words carefully, you'll notice that he doesn't really claim that his product is what you and I would all a "time machine".
All he gurantees is that the machine will get you to the future - something we all do on a regular basis at the rate of 60 seconds per minute. And he explicitly says in one of his answers: "I have not had any experience with going forward, then coming back."
Another hint:
"Also, I would not consider myself overly wealthy, but I have used this device several times to find out the results of lotteries"
Note that the seller did not claim he could predict the results in advance! He only used the device to find out the results. Maybe he is selling a radio or a newspaper transcription...
I know what you're going to ask... What about his claimed brief visits to the past?
Well, if you read carefully, you'll notice that the seller NEVER actually mentions travelling into the past. He only said that "I have also visited times past." - but he didn't necessarly arrive there from the present, did he?! We all visited times past. I visited the 1980's, when I was a kid. And it really does seem blurry today... ;-)
I admit the guy got me really curious as to what his "time machine" really is... But I'm just not willing to pay $260 just to satisfy my curiousity.