Sorry if the title is ambiguous, I couldn't find a better one.
I'll make an example to try to explain this with a better way.
Example I buy a weapon for 30 points by click a brick, and I drop this weapon, how can I make it so I don't have to buy it again by clicking the same brick, using events? By the way, I know it would be easy to do this with item saving/loading events, but it's not what am I talking about at all.
If someone already went to Reinforcement's Trench Dig server, they might know what do I mean.