Hi! If your teeth are heavily stained, then veneers may not work well. Keep in mind that veneers are thin; often 0.4mm in thickness and the underlying tooth colour may transmit through the veneers. Dark areas between the teeth make the gums appear dull and would also create and unsightly effect. Crowns encompass the entire tooth and “lava crowns” by 3M Espe have a zirconia inner core that blocks out the discolouration. The fillings would probably have to be redone to ensure that there is no decay. I cannot give you an estimate at this stage, because I am not sure what we need to do to achieve the best outcome. Please come and see us and we will draw up several treatment plans to suit your budget. Sincere regards Michael.