It is the lowest price per bottle, and also the biggest commitment.
Six bottles at $49 each come to $294, labelled a 180-day supply, with free US shipping and a Best Value tag. Best Value here means lowest price per bottle, not proof that the product suits you.
The guarantee is 60 days, so most of the supply falls outside it.
It makes sense only if you already know the product suits you, or you accept that after day 60 the money-back option has ended. For a first purchase, a smaller package leaves less at risk. Our post on the Best Value and Good Value labels covers the wording.