We have 5000 products at our webstore. We can not use magento default feature related products & upsell, cross-sell products. Is there any customize code or modules which can implement to display automatic related products and category based up-sell & cross-sell products? We are using magento 1.9.2.
There are many Commercial extension available for set up related, cross sell & up sell products automatically.
You can also check free community extensions below: