Since the opening of StickyMC it is possible to rent plots in the spawn. These plots can only be used to build shops. You can read how this works in this post.
Step 1: Make sure you have enough money and rent a plot in spawn.
In spawn, as soon as you walk out of the gate, there is a sign with all the plots on the right. This shows all plots with the corresponding prices. Which plot is which, you can see through the posts that are next to each plot.
Please note, if you click once on a sign, your money is immediately debited and the plot is yours for 30 days. You don't have to confirm this, so watch where you click.
Step 2: Add your friends and fellow players to build on the plot.
By typing the command "/ arm addmember [player name]", you allow players to build and use things on your plot. To remove their permission from your plot, type "/ arm removemember [player name]".
Step 3: Extending your rental.
By pressing the board next to your plot, or the general shot board, you automatically extend the rent of your plot. This is also done without confirmation and happens automatically after clicking.