DD (nearly 3) has been invited to a joint birthday party of a friend and another girl we've never met. Do I have to buy the same value of present for both little girls? The one we know we have exchanged birthday gifts with at age 1 and 2 so it is 'traditional', otherwise being a bit of a 'less stuff needed in the world', I'd be tempted to bring nothing or a token tiny thing. Advice appreciated...