You have a product,
part of a line extension.
It doesn’t sell well.
Many folks who do buy it,
dislike the product.
You might as well
give it away for free.
What do you have to lose?
Your entire future.
If you give this product
away for free,
many prospects
who were considering buying
your related products will try it.
They will likely hate it
(as the others did)
and then they won’t buy
another product from you
again.
They’ll tell others
your product is garbage,
advising them to get the free product
if they are still considering it.
This is how brands die.
Only promote your good products.