Blood Strike Gold?

Hello fellow Strikers

So I recently started playing this game and have a few doubts regarding Gold:

What exactly can you buy with timed Gold?

Since all Gold is in the same place how can I tell how much of it is timed and how much is not?

When I buy something with Gold (assuming it is something that can be bought with either type of Gold) does it spend the timed one first or does it take the other 1st in hopes that the timed one expires?

How can I check the expiration date of the times Gold?

Thank in advance for any help

Happy Striking!!!