I think it's better to invest that $40 in something else. Not super practical as you wouldn't really get much use aside from sitting around the house and many babies wouldn't like that it's only legs in. I'd think sizing would be tricky as well. It's the kind of thing that would be useful for kangaroo care in the NICU maybe but not so much for other purposes.
Re: Nuroo (babywearing) shirt
Breastfeeding Counselor with Breastfeeding USA
Babywearing Guide ** Newborn Carriers
Cloth Diaper Guide
Safe Bed Sharing Info