Depends. Fillings or other dental restorations vary in cost from area to area. However, one thing is consistent: the cost of the filling varies depending on its complexity. We measure that by evaluating the number of tooth surfaces that the filling will restore.
Don't base on price. Sorry, that's difficult to answer w/o knowing what kind of filling you'll need, how many surfaces are involved & how complicated the procedure will be. If you don't live in singapore, i would highly recommend that you not get the filling done there. Because, even if it's $1, what are you going to do if you have problems or when it needs to be repaired or replaced. I would rec someone local!