well, i would ask these questions:
who is the blogger
what are their site hits and how many subscribers do they have
what is their advertising revenue
how long have they been blogging and have they won any awards, mommy blogger awards, nomo awards, anything like that.
among other questions.
as for the send it out buy a box thing, i only have heard of a few of them actually being bought, birch box and one other.
as for me i don't do these things, it doesn't seem like a very good return.