A dream with a check (or cheque), can suggest that your way of thinking in some area of your life is outdated. Alternatively, the dream can imply that you feel indebted to someone, or that you are being rewarded for your efforts in some part of your waking life. A blank check can represent your potential in some part of your life.
A paycheck can imply that you will be or are being rewarded for your fruits of labor. If the amount on the check is lower than expected then it suggests that you feel like you are being undervalued in some part of your waking life, while a higher than expected amount can imply that your efforts will pay off.