Controlling the stocks from Products module by adding custom fields and then managing it from Quotes/Invoice Save Hooks would be a straightforward solution for newbies. Order cancellations or returns can also be managed within those hooks as if the Invoice status is cancelled or returned, that would add to the Product stock.
Anything more complex like having LOT/BATCHES or Manufacturers and Suppliers or having Stock Quantity in Line Items like below would require custom development.
