To add a manual price to a line item, select the price and quantity you want to add a manual price for in Material Costing.
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This will open CQ Price Selector. Click the + in the top left-hand corner.
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An Enter Price popup will appear asking you to fill out (at minimum):
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Supplier Name (start by typing in the name. If there is an option, select the supplier. If not, use the + to add the supplier)
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Unit Price
You can add other additional fields and use See More to add more details.
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After saving, this will redirect you to CQ Price Selector. You can identify the manually inputted pricing option with the pencil icon next to the Supplier Name.
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Tip: Should you wish to select this price for all quantities, click "Apply to All Quantity" in the bottom right-hand corner of the window.