  We consider the prophet inequality problem for (not necessarily bipartite)
matching problems with independent edge values, under both edge arrivals and
vertex arrivals. We show constant-factor prophet inequalities for the case
where the online algorithm has only limited access to the value distributions
through samples. First, we give a $16$-approximate prophet inequality for
matching in general graphs under edge arrivals that uses only a single sample
from each value distribution as prior information. Then, for bipartite matching
and (one-sided) vertex arrivals, we show an improved bound of $8$ that also
uses just a single sample from each distribution. Finally, we show how to turn
our $16$-approximate single-sample prophet inequality into a truthful
single-sample mechanism for online bipartite matching with vertex arrivals.
