In some cases when a person is donating items (not cash) to a charity the charity does not give a receipt for the amount of the FMV of the item but instead the lesser of the fair market value and what the person paid for the item.  Here is a CRA note on the subject.

http://www.cra-arc.gc.ca/chrts-gvng/chrts/prtng/rcpts/dmdfmv-eng.html

Deemed fair market value rule

What is deemed fair market value?

The deemed fair market value rule states that, under certain conditions, a receipt issued for a non-cash gift must be issued for the lesser of the gift’s fair market value and its cost to the donor (or in the case of capital property, its adjusted cost base) immediately before the gift is made. The conditions are as follows:
• the gift was donated to the charity after December 5, 2003; and
• the gift received by the charity was initially acquired by the donor as part of a tax shelter arrangement; or
• the gift was acquired less than three years before the time of donation; or
• the gift was acquired less than ten years before the time of donation, with one of the main purposes being to gift the property to a qualified donee (for example, a registered charity).

Example
A donor purchases a work of art for $300, and six months later donates the work to a registered charity. The registered charity would like to issue the donor an official donation receipt. Prior to gifting the art, the donor has the work appraised at a value of $1,000.

Because the donor is gifting the art within three years of having purchased it, the charity must issue a receipt for the gift at the lesser of its fair market value and its cost to the donor immediately before the gift was made. In this example the official donation receipt must be made out for $300.

Note
If a donor makes a gift in kind (non-cash) donation to a charity, for which a receipt is issued, and fails to notify the charity that the gift in kind is subject to the deemed fair market value rule, the value of that donor’s gift could be reduced to nil.

Gifts exempt from the deemed fair market value rule (normally assessed at fair market value):
• gifts made as a consequence of a taxpayer’s death;
• gifts of inventory;
• gifts of real property situated in Canada;
• gifts of certified cultural property (special valuation procedures apply); and
• gifts of certain publicly-traded securities.

If the registered charity is not a private foundation, the following property is also exempt:
• ecological gifts (See the Canadian Ecological Gifts Program for applicable valuation procedures).

References
• P113, Gifts and Income Tax
• Registered Charities Newsletter No. 24 – Late Summer 2005