Mattresses in a box have exploded in popularity in the past few years. They give you the fresh feeling of a new bed without the hassle of getting it home from the storePurple is one of these boxed bedding companies, but their mattresses stand outrather than foam or springs, Purple uses Smart Comfort Grid technology for its sleepers.SEE ALSO: These are the best mattresses of 2019The grid design is optimized when covered with Purple sheets that are stretchy enough to flex with the mattress. Now until March 25, Purple is actually giving away free sets of sheets when you purchase a mattress. Thats a value of up to $129. Read more...More about Mattress, Sleep Tech, Mashable Shopping, Shopping Ziffdavis, and Lifestyle Click here to read full news..