from tkinter import *
from tkinter import messagebox
import json
import os

window = Tk()
window.title('Взнос')
window.geometry('430x500')
window.resizable(False, False)

def clicked():
     with open('bank', 'r') as file:
        text = json.load(file)
        score = float(text["score"])
        messagebox.showinfo('<Баланс', 'Баланс банка = {score} Eth.'.format(score=score))

send_btn = Button(window, text='Провести расчет выплаты', command=clicked)
send_btn.pack(**base_padding)
window.mainloop()