From $49 / bottle is the headline price. It describes the best case.
$49 a bottle is the price in the 6-bottle pack, which totals $294. The 3-bottle pack is $69 a bottle and the 2-bottle pack is $79. So from means the lowest price, and you reach it only by buying the largest pack.
The $79 price of the 2-bottle pack is the same as the stated regular price.
Compare packs by what you pay in total and per day, not by the headline. Bigger packs lower the daily cost but put more money behind a decision you cannot fully test within the 60-day guarantee. Confirm the final figures at checkout.