As I've posted before, you have to watch the "add-ons" (taxes and $10 shipping) - you can get a good deal or a bad one. Case in point: winter (November-March excluding around Christmas) west coast to London on United: a couple of weeks ago somebody got it for $337+108=$445; good but (depending on fare wars) not great. This week somebody bid $451+108=$559; that seems way too high for low season, even with airfares rising.

On the other hand, my $490 (total) roundtrip SFO-CDG in September, nonstops on the dates I asked for, was definitely a winner.