I dislike uggs. The name is very appropriate for me "Ugg!" I can understand you wanting to get rid of them!!
Can you not exchange them for something nicer instead of selling? The giver wont have to know, unless they come out and ask... It will be easier to say you exchanged rather than you sold them. Just sayin..
no receipt & im in japan. i havent seen uggs for sale in my city yet. Vans are popular here.