I'm planning on purchasing a Greenbull 5x (hybrid laser/spindel). What other expenses will I have for having a fully operationel machine

You will need to make sure you have a 220 volt outlet near the machine. You will need some wire to connect the electronics unless you purchase the redFly, redLear or redSprout plug and play electronics. To maintain cooling for the spindle, you will need some silicone tubing to provide for water exchange within the spindle, a bucket and pump to pump the water. You will need a table built as per the dimensions on the greenBull page: https://www.buildyourcnc.com/greenBullCNCMachineKit.aspx For cutting material, you will need end mills which are consumables that will be purchased frequently as they wear. The pump and silicone can be found here: https://www.buildyourcnc.com/category/pneumatic-hydraulic