"No cost rollup is found for this item. Activate the item cost price"

Recently while working on setting up an environment for a customer using AX 2012 CU7, I came across the error "No cost rollup is found for this item. Activate the item cost price". Typically you get this issue when you have standard cost items with no active prices. In our case we set up all the prices for cost/purchasing/sales and activated for all sites for a standard cost item, yet we were not able to receive a purchase order with this standard cost item. We kept getting this error message. Below is how I resolved this issue:

1. Make sure that the "BOMCostBreakDown" configuration key is active. Although, in our environment we were not using BOM, yet - I think due to a bug - AX requires for this configuration key in order to overcome this issue. Go to System Administration -> Setup -> Licensing -> License Configuration

          BomCostBreakDown configuration key is located under Trade->Bill of Materials.

2. Reactivate Item prices for all the standard cost items. This will populate InventItemPrice and InventItemCostGroupRollup tables.  Prices were missing in InventItemCostGroupRollup table which was causing this issue.