My son is now three, so we finally decided to buy him a big (twin) bed since he is a big boy now. He is currently using his old bed though which is still big enough for him, but since we are planning to have him sleep in his own bedroom, we wanted to get him a new bed.
I saw a lot of nice bed frames that my son will probably like. After getting the frame, we will get a mattress that he will like, meaning soft and bouncy enough for a 3-year-old.
I'm sure he is excited and I'm excited too.