Bot to shop written in Python

Hello,

I need a simple bot written in python for shopping. Its functions are limited to:

handling a .txt file

retrieving text from it (line by line)

pasting it into a text field

clicking the search button

if the product is available, buying it

doing the same thing over and over again every second

I want the code to be described and clear, because in the future I will be editing it myself. I will enter url and id of elements on the page by myself. Boot from txt file should only read data, which will be systematically completed. I want the program to work reliably on google chrome and opera.

More information will be given by phone