You need to include your inbound freight expenses in your inventory asset. Doing so better matches your expenses to your income.
1) Enter a Bill (to your Inventory Vendor) using standard Inventory Parts.
2) Include the freight as part of the cost of the inventory parts, spread out as applicable (for instance, with an item cost of $5.00 and a freight charge of $0.50, change the cost to $5.50).
3) On the Expenses tab, enter a Negative amount using an offset account equal to the total freight for all inventory listed. This will cause the bill to be the appropriate price for the original vendor.
4) Create the 2nd Bill to the freight vendor for the amount of the freight. Have it go to the same offset account that we put as a negative on the first bill.
The secondary bill will zero out the account, so the only expense will be recognized when the item is sold per normal cost of goods sold process for inventory items.