i'm from philippines can i book a roundtrip ticket for at least 2 months?

i mean, we'll be going to macau this april and we're planning to stay there for almost 50days, i know the visa is only valid for 30days but we'll make a U-turn to mainland to get a new visa which is good for 20 days after we use the first one. it's such a waste if i'll book for only a month worth of roundtrip ticket. thanks