With baby no 2, after the 20 week scan. With baby no 1, after the 12 week scan..and then we had a mmc. I now have to look at keepsakes and be reminded! Couldn't take them back, and it didn't feel right giving them to the next baby.
Having said that, buying something isn't got to change what nature will decide. Your call really!
But pg is long, and you're better to wait imo! Baby no 3...hmmm....2 weeks before he was born 