a doubting Thomas - someone who would not believe anything without physical evidence
ex. You will never be able to persuade him by using words alone. He's a doubting Thomas kind of guy.
a dime a dozen - something quite common and very easy to get
ex. As a famous antique collector, it wouldn't reflect well on your image to buy something which is a dime a dozen.
a blessing in disguise - something which one might think is an unfortunate incident at first, but turns out to be something really good after all
Ex. Getting fired from that company resulted to my starting my own business. It's really a blessing in disguise.
A bird in the hand is worth two in the bush - Having something that is certain is much better than taking a risk for more, because you cannot be sure you would get it, and might even lose what you already have.
Ex. You've already been offered a sure job in the shopping mall. Why turn it down in order to look for another? Remember that a bird in the hand is worth two in the bush.
