Patryn is right. It's a good price whatever model it is.
It's just that the M2 version 710 (HS) will usually cost about US$20 more. If it is that model, then it's an even better price, obviously. From what you say though, I have a feeling it might be the 154CM stainless version - 710.
As Alpha is driving at though, you might well have a preference for M2 over the other, so it would be a good idea to check that. I'm assuming that the knife is one or the other - not an older model still, which you might also want to find out.
The phosphor bronze washers are preferred by all BM users. More robust and smoother ultimately. They were introduced in the Axis folders by BM about a year ago I think. So the vintage of the knife would tell you something. You can also tell what's there just by looking at the pivot area - don't have to dismantle. The old washers are black - synthetic. The new ones are bronze coloured, astonishing as that might seem.