Merlin,

Foods are quite cheap and nice at those old shophouses along roadside.
I would rather advise u to skip restaurant if your budget is tight.
I went to yung kee restaurant to try their goose drumstick and felt nothing special. The meal alone cost HK1,122. Shock us! We just ordered half chicken, half duck, 8-10pcs roast pig and tofu dish only.

As for mtr, u can buy tourist card and travel unlimited for 24hrs! Inside got discount coupon for attraction too!