I put an addition on a house that has cedar plank siding. I want to reside with the same look but cedar is too expensive. Is there any other type of vertical plank siding that is flat and is not beveled?

Check into Hardie Plank cement siding. Is flat, doesn't rot, won't ,burn can be painted or stained. --also other brands out there

Whatever you do, do not use the hardiplank siding. Is total garbage. It's hard to install (breaks and chips easily), does NOT look like wood... It's crap. I wouldn't give it to my worst enemy.

Are you going to paint or stain? If you decide to paint, you can get pre-primed siding for a fraction of the cost of clear cedar.