"expensive grounds to keep up"
they ware talking about their new restaurant on the beech
A; it won't work as residential place, we'll make a restaurant out of this land.
B:Expensive grounds to keep up.

Question

Answer

It means the same as "It's expensive to have this place" or "It's expensive to have this business". The "Grounds" means place/business while "Keep up" is like saying "to have" or "to continue doing business".