In the past, I once owned a Star Rod, Melon Sword, & Efficiency 7 DPick.

Efficiency 7: Best way to make money, to be efficient, ExtCommands+(+) & Pyro+ will help a lot. With ExtCommands+(+), you won't need someone to always repair your tool once it's nearly broken. Plus Pyro+ will give you the opportunity to not die if/when you fall in lava while mining. With the Efficiency 7 DPick, you're given the option to clear land. But overall, if you want to make an efficient amount from mining, it depends on if your mine is good or not.

Melon Sword: Quite easy to make money, you don't need any features to have a tool like this. It will help though if you have ExtCommands+(+) because it will indeed help you enchance your making of more money from melon farming. The only downside I see to this tool is that it may be boring to some users.

Star Rod: One of the easiest a way to make money like the melon side. Just like the melon sword, you don't need any features to have a tool likes. But it will indeed help a lot of you do. With this tool, like a Mwlon Sword, you can multi-task with it. The only downside I can see to this tool is the amount it makes per hour. To make a lot of money per hour you will a higher fishing level.