Nice to meet you dude, and I hope everything goes well with the selling. I think the best thing to do is have a figure in mind you're going to use to set yourself up selling, and also keep track of what each thing was bought for.

On some items you could get lucky, and on some you might be able to double, triple, or quadrouple your money, which is grand. Obviously the item needs to sell to do so though.

It's something I've wanted to do for a while, and I'm glad to have finally started.