Q: How do I fix this "TypeError: 'str' object is not callable" error? I'm creating a basic program that will use a GUI to get a price of an item, then take 10% off of the price if the initial price is less than 10, or take 20% off of the price if the initial price is greater than ten:
import easygui
price=easygui.enterbox("What is the price of the item?")
if float(price) < 10:
    easygui.msgbox("Your new price is: $"(float(price) * 0.1))
elif float(price) > 10:
    easygui.msgbox("Your new price is: $"(float(price) * 0.2))

I keep getting this error though:  
easygui.msgbox("Your new price is: $"(float(price) * 0.1))
TypeError: 'str' object is not callable`

Why am I getting this error?

A: You are trying to use the string as a function:
"Your new price is: $"(float(price) * 0.1)

Because there is nothing between the string literal and the (..) parenthesis, Python interprets that as an instruction to treat the string as a callable and invoke it with one argument:
>>> "Hello World!"(42)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'str' object is not callable

Seems you forgot to concatenate (and call str()):
easygui.msgbox("Your new price is: $" + str(float(price) * 0.1))

The next line needs fixing as well:
easygui.msgbox("Your new price is: $" + str(float(price) * 0.2))

Alternatively, use string formatting with str.format():
easygui.msgbox("Your new price is: ${:.2f}".format(float(price) * 0.1))
easygui.msgbox("Your new price is: ${:.2f}".format(float(price) * 0.2))

where {:02.2f} will be replaced by your price calculation, formatting the floating point value as a value with 2 decimals.

A: this part :
"Your new price is: $"(float(price) 
asks python to call this string:
"Your new price is: $"
just like you would a function:
function( some_args) 
which will ALWAYS trigger the error:
TypeError: 'str' object is not callable
