python vending machine program- I have two questions

1. I'm creating a vending machine program that simulates the action through a loop that ends when the user enters 0 but it doesn't print "0 to cancel" in the output. I tried putting it at the top before the if statements but, I want to be able to enter an input after the if statements are printed. So how could I fix that?

2. It says that user_val is undefined when I equal it to 0 but I did define it at the bottom.

If someone could help please!

print("*********************************")
print("Welcome to Vending Machine Bravo!")
print("*********************************")
print("If you would like to make a selection, please insert the appropriate currency into the machine.")

# Currency deposit [tag:tag-name]
num_5Dollars = 5.00
num_Dollars = 1.00
num_Quarters = .25
num_Dimes = .10
num_Nickels = .05
num_Pennies = .01 
currency = [num_5Dollars, num_Dollars, num_Quarters, num_Dimes,    num_Nickels, num_Pennies]

if num_5Dollars == 5.00:
    print("5.00 for $5 bills")
if num_Dollars == 1.00:
    print("1.00 for $1 bills")
if num_Quarters == .25:
    print(".25 for Quarters")
if num_Dimes == .10:
    print(".10 for dimes")
if num_Nickels == .05:
    print(".05 for nickels")
if num_Pennies == .01:
    print(".01 for pennies")
if int(float(user_val)) == 0:
    print("0 to cancel") 

user_val = float(input())

Your user_val defined under the line if int(float(user_val)) == 0.

And if you want to say to user 0 to cancel, you don't need to check int(float(user_val)) == 0, because while this doesn't happened, it won't print this instruction.

So basically, you need to remove if int(float(user_val)) == 0: line