Before I explain what, I meant from my Skript suggestion I would like to thank you for helping me out with this Skript.
There is one error with what you completed so far in the image below.
As for what I meant after selecting 2 points for the wall (with permissions for the commands below)
They can create a temporary buyable unbreakable wall using the command you would type /coinwall create [coinwall name]
Which would make the wall temporary unbreakable until someone right clicks the coin wall with the correct amount items using a command /coinwall price [coinwall name] [amount]
/coinwall setcurrency [item] "It sets the currency using the held item the must being only holding 1 of the currency"
(For example, the currency would be diamonds and using the command above you can set a different price to buy each of the walls (as I would like to set different prices for each wall created)
Also, a command to remove a Coinwall using /coinwall delete [coinwallname]
And a command to see all the created walls (with their prices to buy said wall) using /coinwall list.