You can set product specific limits on net price, margin, discount %, and markup % in the limits section of the product pricing widget. Each limit is an optional field for the product.
In the case in this image, the minimum net price has been set to $100.00. This means that if the net discounted price of this product is below $100.00 on any quote, the user will not be able to save the quote and will receive a warning letting them know the price is below the limit.
NOTE: If you have multi-currency enabled and are using exchange rates set in company settings, then the Min Net Price will automatically be adjusted based on the exchange rate for any proposal created in a different currency.
If you have specified multiple limits for a product, all limits will be checked and an warning will be displayed to the user if any of the limits are exceeded.