Planning for macau trip with family of 4. give important attractions to visit in 2-3 days and cost.

For your 2-3 days stay, I suggest you visit the following places:
Ruins of St. Paul’s, Monde Fort, Senado Square, Museum of Macao, A-ma Temple, Macao Tower, Fisherman’s Wharf, Venetian & City of Dreams
BTW, the Rua da Cunha is the best for dining. You can find many restos and snacks there.

Most hotels in that city is expensive, the average price is 700 – 800MOP per night. I suggest you live near Avenida de Almeida Ribeiro, where you can find a lot of hotels in different standards. The Central Hotel Macao is an economical hotel, have a try.