Reskin, the purpose of having things cost so much is to balance the economy & to also make the game more fun. Redstone isn't sold because buying it takes no time but actually mining for it may take a while ( using a ore generator ) - Time = Money. That's how Dan has customized this server. As you probably know redstone is used to make farms & so are hoppers. To sum it up to make money, you need money , Thats how the economy gets balanced out . Hoppers, dirt, redstone all cost a ton of money ( as you know ), all of these items are used in farms, farms that make millions of dollars.

Your island doesn't focus on farms I don't think - To make money you need to have
farms. Farms = Money, Money = Effort, Effort = Time <---- How the server works.<br />
Basically to do anything you need to start off by investing a lot of time into the server - First you need to get farms up (which takes a lot of time), then you can decorate your items with costly items (Glass, Dyed Wool, etc)