We have several items that I have made to have a Special price. I did this by going to "Catalog|Specials|New Product" I then select the product, give it a Special price and Insert. On the site, it looks just fine - showing the correct Special price. However, after adding the item to my cart I am then shown the normal price of the item.
Select "Specials..." from the left nav and add the "Youth Retro T-shirt" to your cart. It will be added, but the price shown (and calculated at check out) is the original price.