I need to change row subtotal with custom price.
Product X : $90
Applied Catalog Discount : $80
User trying to add : 4 Qty
User can only purchase 3 items with discounted price. For the remaining user needs to pay regular price.
Here in this scenario final subtotal calculation will be:
3 Qty = 3 * $80 => $240 (Discounted)
1 Qty = 1 * $90 => $90 (Non Discount)
Row Sub Total = $330.
How can i achieve this.?