The "free" part at descarga.com is "listening " .
As to actually downloading "free" songs, I would personally hesitate to do so. Being a DJ ( as well as teaching ),I like most DJs, frown upon the free concept..... reason ?.. musicians are never consulted or compensated,, and gain no reward for their efforts.
I'm NOT against "free" stuff, but as they say " there aint any free lunches " .
I would also say that, I think Jonathon is commendable for the access he gives to vids, with no cost .