Error: attempt to perform arithmetic on global 'cost1' (a table value)?

So, I am trying to store the cost of something in a table. But the issue is that the cost will not go up and the error comes up. Here is the script.

cost1 = {80,160,200,210,230,250,300,301,302,303,304,305,306,307,308,309,310,311}
CostChange.OnServerInvoke = function(player)
	local cost = player.UpgradeCosts.BackpackUpgrade
	local lev = player.backpack.WeightLevel1
	lev.Value = lev.Value + 1
	cost.Value = cost.Value[#cost1 + 1]
end

Thanks

This is kind of difficult to answer, you've just given a script with some unknown variables. We hardly know what you're trying to do.

But the error is that you're trying to take a table, and add 1 to it. Once again its hard to find out your intention but if you're trying to add 1 to the table as a value, do table.insert(cost1, 1)

But if you want to add every number in the table by 1 then you're better off just taking every table entry and adding 1 to that, instead of trying to do math on a table object.