NumberValue doesn't change/display, why?

NumberValue Addition = 1

IntValues Multiplier = 1 Adder = 1

This script is in an Image Button

wait(0.6)

addv = script.Parent.Parent.LemonBuy.Addition.Value
multiv = script.Parent.Parent.LemonBuy.Multiplier.Value

button = script.Parent

ting = 0

function onClick()
if ting == 0 then --debounce check
	ting = 1 --activate debounce
	local plr=script.Parent.Parent.Parent.Parent.Parent
	local stats=plr:FindFirstChild('leaderstats')
		if stats ~= nil then --If moneyholder exists then
			local cash = stats:findFirstChild("Money") --Get money
			cash.Value  = cash.Value +(addv*multiv)
			wait(0.8) --wait-time before button works again
		end		
		ting = 0 --remove debounce	
	end	
end
button.MouseButton1Click:connect(onClick)

Connecting with this is another script... This script is in a TextButton.

wait(0.6)

local cost = Instance.new("NumberValue")
cost.Value = 4
costv = cost.Value
local plr=script.Parent.Parent.Parent.Parent.Parent
local stats=plr:FindFirstChild('leaderstats')
local money=stats:FindFirstChild('Money')
local multi = Instance.new("NumberValue")
multi.Value = 1.00
multiv = multi.Value
print("Run 1")
addv = script.Parent.Addition.Value
adder = script.Parent.Adder

button = script.Parent

ting = 0

function onClick()
if ting == 0 then --debounce check
	ting = 1 --activate debounce
		local stats=plr:FindFirstChild('leaderstats')
		if stats ~= nil then --If moneyholder exists then
			local money=stats:FindFirstChild('Money') --Get money
			if money.Value>=costv then
				money.Value = money.Value - costv
				costv = costv * (multiv+0.07)
				addv = addv + adder.Value
			end --increase amount of money by the number displayed here (500)
			wait() --wait-time before button works again
		end		
		ting = 0 --remove debounce	
	end	
end
button.MouseButton1Click:connect(onClick)

function force_decimal_places(num, places)
	if type(num) ~= 'number' or type(places) ~= 'number' then
		return 'NaN' --not a number
	end
	local mult = 10^(places or 0) --set up rounding places
	num = tostring( math.floor(num * mult + 0.5) / mult ) --round
	local dot = string.find(num, '%.')
	if not dot then --easily add zeros to an integer
		num = num..'.'..string.rep('0', places)
	else --some after decimal?
		local after = string.sub(num, dot + 1)
		if after ~= places then --if it doesn't already round to exact places
			num = num..string.rep('0', places - #after)
		end
	end

	return num --returns a string (otherwise the zeros would get truncated)
end

print("Run 3")
while wait(0.1) do
local dollars2 = force_decimal_places(costv, 2)
script.Parent.Text = 'Buy: $'..dollars2
end
print("Run 4")