I have seen more and more instore promotions recently where if you buy one thing or spend x amount, you can get something else at a discounted price.
For example: Woolworths are doing buy Pokemon Pearl DS together with Pokemon Diamond DS and get some other DS game for £10.
W H Smiths ran Spend £30 and get Harry Potter Book 7 for £5
So here's the question. If you take up these offers and then return the other items do you get to keep the discounted item at no additional cost?