[bjimster1]

Its all explained in the manual. But anyways regardless of how you acquired an item you put it in the BOM at market price.
http://www.usfirst.org/uploadedFiles/Community/FRC/FRC_Documents_and_Updates/2007_assets/Manual/8-The_Robot,Rev%20G.pdf

8.3.4.3 Cost Accounting Rules
<R49> The costs of all non-2007 Kit parts and materials used in the construction of a ROBOT (as
defined in Section 8.1.1) must be recorded (in US dollars) by the team, and a list of all such
items and their costs presented at ROBOT inspection.

<R50> All costs are to be determined as explained in Section 8.3.4.4 - Additional Parts - Cost
Determination.

<R51> The total cost of all non-Kit Of Parts items must not exceed $3,500.00 USD. No individual
item shall have a value of over $400.00. The total cost of components purchased in bulk
may exceed $400.00 USD as long as the cost of an individual component does not exceed
$400.00. The following items are EXCLUDED from the total cost calculation:

• The cost of any non-functional decorations
• The cost of individual fasteners, adhesives, or lubricants, unless any one component exceeds $1.00
• The costs of SPARE PARTS. A SPARE PART used as a direct replacement for a failed or defective ROBOT part (either Kit part or non-Kit part) that has already been included in the cost accounting is covered by the accounting for the original part
• All costs for the construction of the OPERATOR CONSOLE

<R52> The costs of additional non-spare robot control system components obtained from Innovation First Inc. are to be included in the above $3500.00 limit.

there's still another section to this for additional parts. just click the link and go to page 20