No need to tell him. I'm going to edit his game for all the edits and I'm going to PM with the link later.
Wouldn't it be much better to just tell him how to do it? He would benefit a lot more from learning how to do a simple condition check, than from you editing it for him.
@ Lac
What you need to do is make a conditional branch that checks if they have enough currency to buy the item.
1: Conditional branch button.
2: Page to find the Currency option.
3: Check the currency/gold box.
4: Enter the amount of gold they need to buy the item.
That should be enough to get you started, in order for me to really help you out, I would need to see the event also.