L.D.
My oldest went through this and we used "bad dream go away spray". We also told him that when he did have bad dreams, that he was to look at whatever was scaring him and say, "Monster (whatever it is) GO AWAY!!! I don't believe in you! You aren't real!" We had him practice saying it with us and had him keep doing it until he was very forcefully saying it with belief. It got to the point where he would almost giggle when we were "practicing". Maybe it was the sheer repetition of saying it, but the dreams calmed down pretty quickly. Of course he still has one once in a while...he's 9 1/2 now. But they are not anywhere near as often as they were when he was 4. ;)
Personally, my husband used to have them all the time as a kid too. He was more afraid of his mother than anything so he would lay in bed too petrified to move. We didn't want our kids to feel that way. We want them to know we are always there for them. So we let them come in and sleep with us when they have had a bad dream. I can tell you that at 9 1/2, he isn't in our bed every night. In fact, I would say if he still comes in our room once a month we are lucky. I would say even more time than that passes in between, especially since now that he is older, there are more times when we can sit with him for a few minutes, calm/reassure him, and he will go back to sleep in his own bed.
Good luck!!