Fix bin price same as buy price result error

[gfanzh]

No description provided.

[gfanzh]

Also updated core/watch.py to not rely on lowest bin since it's pretty flaky.
This might be controversial. Let me know if you don't like it.

[hunterjm]

I like the fix for same bin/buy pricing, but I'm not sure about the auto-update using the third lowest price. My reasoning being that, in my opinion, it is always better to set our threshold for buying players too low than it would be to set it too high. For example, if you are working with players in the 1-2k range, the difference of 100 coins could be the difference between whether or not it sells. I don't want to buy 10 players for 1800 if there are two BINs at 1700.

That being said, I know that the PC market has far less players, so the numbers can be more flaky than console. Maybe we add another setting that lets the user choose which to use?