Is there such thing as a formula sample box?

I have been exclusively pumping breast milk for my baby for five months but am now struggling to keep up with her appetite and need to supplement 1-2 bottles of formula a day. I have tried several different kinds and the baby gags, shudders and then spits them all out. She just will not eat anything I’ve tried. Is there any such thing as a box that comes with samples of different kinds of formula? I’ve spent so much money on wasted powder. I signed up for similac strong moms and the enfamil rewards program weeks ago hoping they’d send small samples but have gotten nothing.