Room Exploration; Issues with collecting items from a dictionary

In testing out your code it appeared where you were getting stuck was with the "getting" of items within a room. With that, I focused on tweaking the "get_item" function. Following is a copy of your code with some tweaks to the dictionary so that one could move about rooms a little easier and a refined "get_item" function.

rooms = {'Start room': {'name': 'Start room', 'west': 'West room', 'east': 'East room', 'north': 'Hallway',
                        'text': 'You are in the Start room.'},
         'Hallway': {'name': 'Hallway', 'north': 'Hallway2', 'south': 'Start room', 'item': 'chips',
                     'text': 'You are in the Hallway.'},
         'Hallway2': {'name': 'Hallway2', 'north': 'Hallway3', 'south': 'Hallway', 'item': 'soda',
                      'text': 'You are in the Hallway2.'},
         'Hallway3': {'name': 'Hallway3', 'north': 'Final room', 'south': 'Hallway2', 'west': 'Side room', 'item': 'stick',
                      'text': 'You are in the Hallway #3.'},
         'Side room': {'name': 'Side room', 'east': 'Hallway3', 'item': 'cookie',
                       'text': 'You are in the Side room.'},
         'Final room': {'name': 'Final room', 'south': 'Hallway3',
                        'text': 'You are in the Final room.'},  # boss room
         'West room': {'name': 'West room', 'east': 'Start room', 'item': 'crown',
                       'text': 'You are in the West room.'},
         'East room': {'name': 'East room', 'west': 'Start room', 'item': 'cape',
                       'text': 'You are in East room.'}}

item_list = ['chips', 'soda', 'stick', 'cookie', 'crown', 'cape']  # Added this for a simplified check of what items have been acquired

def get_item(item_wants, current_room, inventory):  # Enhanced this function.
    if 'item' in rooms[current_room]:
        item_can_get = rooms[current_room]['item']
        if item_wants != item_can_get.lower():
            print(f'There is no {item_wants} in this room')
        else:
            got_item = False
            for i in range(len(inventory)):
                if (inventory[i] == item_wants):
                    print("you already have this item")
                    got_item = True
            if (got_item == False):
                print(f'You just picked up {item_wants}')
                inventory.append(item_wants)
            got_all = True
            for i in range(len(item_list)):
                if (item_list[i] not in inventory):
                    got_all = False
                    print("You need to find", item_list[i])
            return item_wants

def help_file(DIRECTIONS):
    print(f"Use {DIRECTIONS} to move! If you would like to quit, type 'quit'.")


def get_input():
    arg = ''  # default if no arg
    input_list = input('Enter move, get or quit:').split()
    command = input_list[0]
    if len(input_list) > 1:
        arg = input_list[1]
    return command, arg

def main():
    inventory = []
    DIRECTIONS = ['north', 'south', 'east', 'west']
    current_room = 'Start room'
    while True:
        # location
        print('You are in {}.'.format(current_room))
        print("Inventory:", inventory)

        # get user input
        c, direction = get_input()
        # moving
        if c == 'move' and direction in DIRECTIONS:
            if direction in rooms[current_room]:
                current_room = rooms[current_room][direction]
            else:
                print(f'You cannot go {direction} from this room')

        elif c == 'get':
            get_item(direction, current_room, inventory)

        elif c == 'help':
            help_file(DIRECTIONS)

        elif c == 'quit':
            print('Game quitting...')
            break
        else:
            print('Invalid statement')

        if current_room == 'Final room' and len(inventory) < 6:
            print('You lost ! You forgot to collect all the items! GAME OVER...')
            break
        if current_room == 'Final room' and len(inventory) >= 6:
            print('You did it! You collected all the items and are with your cool new friend! The end!')
            break

        print()

main()

Give that a try.