I was recently notified of this offer via email. The website says "Buy 2 x S'well bottles for the price of 1, available for any of these styles, just add 2 of the same style to your cart." (Cheapest item is free).
Shipping was $10 to metro area for me (express is extra).
This stacks on top of the Trove Market's current offer of various S'well water bottles up to 67% off (most started at $60, and various 750mL bottles are half price at $29.95 and some 500mL bottles are $19.95).
If you would like to buy from their wider collection - please see more here noting that these are not BOGOF.
These make fantastic bottles for kids / uni students / office workers. They also make great gifts and secret santa presents.
Designed for performance, S'well thermo bottles will keep cold drinks cold for 24 hours and hot ones hot for 12 - and they look great while they do it.
Keeps drinks cold for 24 hours, hot for 12
18/8 stainless steel, non-toxic, non-leaching and BPA free
Fits in standard sized cup holder
Water won't bead on outside: hands, bags and papers stay blissfully dry
Mouth is wide enough for ice cubes and drip-free sipping
Polished enough for the office, tough enough for any adventure
S’well has teamed up with the U.S. Fund for UNICEF to help provide clean drinking water to children around the world
Material: 18/8 double-walled stainless steel, non-toxic, non-leaching and BPA free