When did official banks become common and was anybody allowed to use them or was it solely restricted by a person's social status, wealth or class?
Forgive me for not knowing the correct terms, but in "historical"/Fantasy movies and video games we often see people buying goods with gold coins? Is that accurate? Would the coins be actual gold if so when did start to see denominations of coins?
Of course I am just looking for a general answer as I am aware how vast the medieval period spans and the many different countries/Kingdoms etc
Are there any good books or sources about Banking/General economy during these periods?
I can't answer very much about banks (they're a late medieval innovation and outside my expertise), but I can tackle a subsection of your question:
Forgive me for not knowing the correct terms, but in "historical"/Fantasy movies and video games we often see people buying goods with gold coins? Is that accurate? Would the coins be actual gold if so when did start to see denominations of coins?
No, it's not accurate at all to think of people buying goods with gold coins. Gold was incredibly rare and valuable in the medieval period and there were no gold coins minted in WesternEurope from the fall of the Roman Empire in the 5th century to the 13th century, when gold coinage began to appear in limited amounts in northern Italy, spreading to France, England and the Low Countries in the 14th century. For the vast majority of the middle ages, there was only one denomination of coin - the denarius or silver penny. The extent to which coinage would have been used in day-to-day life is debated, but it's likely to have been reserved for major transactions, with everyday purchases being conducted through informal credit relations. I've talked in detail about such systems in the past here.
Thank you, it was all very informative. It is much appreciated.