main_menu = ["Drinks", "Snacks"]
drinks = {'Water':60, 'Sprite':70, 'Oasis':90}
snacks = {'Matcha Pocky':80, 'Tako Chips':50, 'Almond Pepero':20}
coin_type = {'10','20','50','100'}

print("Welcome to Vending. We only accept 10p, 20p, 50p and £1 coins. Please insert your credit in PENCE:")
coins = (input("Please enter your coins: "))

while coins not in coin_type:
        print ("The coins you've inputted are invalid. Please try again.")
        coins = (input("Please enter your coins:"))
else:
     print("You've entered", str(coins), " Please select the category you want.")
     print(main_menu)


x = str(input("Choose the category you want. Type NONE to finish."))
if( x == 'Drinks'):
    print(drinks)
    print("Please type in the drink that you want. Type 'NONE' to return to the main menu:")
    drink = str(input())

    if (drink == 'Water'):
        if int(coins) >= 60:
            change = int(coins) - 60
            print ("Your item has been dispensed below. Your current balance is", change)
        elif int(coins) < 60:
            extra_money = input("You don't have enough credit to purchase this item, please insert more credit:")
            while extra_money not in coin_type:
                extra_money = input ("We only accept 10p, 20p, 50p and £1 coins. Please try again.")
            else:
                coins = int(extra_money) + int(coins)
                change = int(coins) - 60
                print ("Your item has been dispensed below. Your current balance is", change)
    elif (drink == 'Sprite'):
        if int(coins) >= 70:
            change = int(coins) - 70
            print ("Your item has been dispensed below. Your current balance is", change)
        elif int(coins) < 70:
            extra_money = input("You don't have enough credit to purchase this item, please insert more credit:")
            while extra_money not in coin_type:
                extra_money = input ("We only accept 10p, 20p, 50p and £1 coins. Please try again:")
            else:
                coins = int(extra_money) + int(coins)
                change = int(coins) - 70
                print ("Your item has been dispensed below. Your current balance is", change)
    elif (drink == 'Oasis'):
        if int(coins) >= 90:
            change = int(coins) - 90
            print ("Your item has been dispensed below. Your current balance is", change)
        elif int(coins) < 90:
            extra_money = input("You don't have enough credit to purchase this item, please insert more credit:")
            while extra_money not in coin_type:
                extra_money = input ("We only accept 10p, 20p, 50p and £1 coins. Please try again:")
            else:
                coins = int(extra_money) + int(coins)
                change = int(coins) - 90
                print ("Your item has been dispensed below. Your current balance is", change)

if( x == 'Snacks'):
    print(snacks)
    print("Please type in the snack that you want. Type 'NONE' to return to the main menu:")
    snack = str(input())

    if (snack == 'Matcha Pocky'):
        if int(coins) >= 80:
            change = int(coins) - 80
            print ("Your item has been dispensed below. Your current balance is", change)
        elif int(coins) < 80:
            extra_money = input("You don't have enough credit to purchase this item, please insert more credit:")
            while extra_money not in coin_type:
                extra_money = input ("We only accept 10p, 20p, 50p and £1 coins. Please try again.")
            else:
                coins = int(extra_money) + int(coins)
                change = int(coins) - 60
                print ("Your matcha pocky has been dispensed below. Your current balance is", change)
    elif (snack == 'Tako Chips'):
        if int(coins) >= 50:
            change = int(coins) - 50
            print ("Your item has been dispensed below. Your current balance is", change)
        elif int(coins) < 50:
            extra_money = input("You don't have enough credit to purchase this item, please insert more credit:")
            while extra_money not in coin_type:
                extra_money = input ("We only accept 10p, 20p, 50p and £1 coins. Please try again:")
            else:
                coins = int(extra_money) + int(coins)
                change = int(coins) - 50
                print ("Your item has been dispensed below. Your current balance is", change)
    elif (snack == 'Almond Pepero'):
        if int(coins) >= 20:
            change = int(coins) - 20
            print ("Your item has been dispensed below. Your current balance is", change)
        elif int(coins) < 20:
            extra_money = input("You don't have enough credit to purchase this item, please insert more credit:")
            while extra_money not in coin_type:
                extra_money = input ("We only accept 10p, 20p, 50p and £1 coins. Please try again:")
            else:
                coins = int(extra_money) + int(coins)
                change = int(coins) - 20
                print ("Your item has been dispensed below. Your current balance is", change)
                if change > 0:
                    extra_item = input ("Would you like to purchase another item?")
                    if extra_item == "No":
                        print ("Thank you for purchasing from Vending. See you next time!")
                    if extra_item == "Yes":
                        x = str(input("Choose the category you want. Type NONE to finish."))