I wish to create a couple of Ubuntu shirts as prize for a coming event. In my country it is very difficult to get dollars($), Euros or any coin. This is the reason for making them here instead of buying them from the store. Will there be any problem in making them. Some of them will be similar to the ones in the ubuntu store but others will have other Ubuntu stuff.
Yes it is possible, so long as you follow the Trademark policy, the trademark page lists the policies (community advocacy probably applies to your activity).
Additional information is provided on the following links
If you have questions, Contact Canonical Legal.