Sales on actual dolls are rare - Cecille and Grace seem to be the exception as they have been on sale twice that I remember. However, there is usually a free ship code that can save some money - I want to say that it usually happens around November, but ends before the cyber Monday sale starts.
Cyber Monday and other sales can be a great way to pick up authentic AG outfits for fairly low prices (I have purchased many outfits in the $12-14 range). The selection is totally random and you have to buy immediately b/c things sell out.
I think, if my girls were just starting out, I would buy them a doll with straight hair (easier to care for - curly & wavy haired dolls are gorgeous, but the hair can be hard to maintain).