Computerised stock control systems are absolutely necessary for organisation and business success when you have many different product lines.
What are computerised stock control systems?
With a computerised stock system you have the ability to see at any given time an overview of any stock levels, any prices and also any invoices associated to those product lines.
Also, you have the ability to tie in the cash registers or any other form of order processing (like internet shopping carts). This means that stock levels will alter when items are sold!
Some computerised inventory control systems can be set up to let the staff know when stock levels are low and some can even re-order those products!
Often these system will work with bar codes, allowing the process to be effortless from scanning new stock/sold stock to printing the price labels automatically with all the revelant pricing information.
Remember there are many options out there, some of which may be more than is required for your business situation.