Please just have 1 method to buy stuff and pass a string and min/max values in lol. Why on earth would you copy paste the same thing into different methods when you could just have 1?
Also, you should just create one method for the buyXSet. Use an array instead of 8 different variables and pass the number of the set you're currently checking into one method that separates them out and buys the appropriate item, instead of making 8 different methods with basically the same contents. Makes it much more concise and clear, and it's easier to expand into different areas of items.