How would I be able to implement a daily reward in this script?

I've been trying to do this for awhile and its been aggravating me. I've looked into daily reward scripts that give a reward daily but don't save cash that has been bought. Here is a script that saves cash but how would i be able to implement os.time() into this?

local DataStore = game:GetService('DataStoreService')
local DSService = DataStore:GetDataStore("PlayerData")

game.Players.PlayerAdded:connect(function(plr)
	local uniquekey = 'id-'..plr.userId
	local leaderstats = Instance.new('Folder', plr)
	local savevalue =  Instance.new('IntValue')
	leaderstats.Name = 'stats'
	savevalue.Parent = leaderstats
	savevalue.Name = 'Cash'
	
	local GetSaved = DSService:GetAsync(uniquekey)
	if GetSaved then
		savevalue.Value = GetSaved[1]
	else
		local NumbersForSaving = {savevalue.Value}
		DSService:SetAsync(uniquekey, NumbersForSaving)
	end
end)

game.Players.PlayerRemoving:connect(function(plr)
	local uniquekey = 'id-'..plr.userId
	local Savetable = {plr.stats.Cash.Value}
	DSService:SetAsync(uniquekey, Savetable)	
end)