$$$-$$$$. It depends on where you are. I don't know there are many dentists out there that charges less than a $1000/procelain veneer, but this can be as high as $2500/veneer, say from a dentist in downtown manhattan, ny. Usually to close a gap in front, you would need two veneers. Doing just one veneer may make one tooth bigger than the other, and can cause an esthetic problem.
It depends... The size of the gap will determine how many veneers are needed to achieve a desireable result. The cost of the veneers is highly variable and is based upon the experience of the dentist, the expertise of their dental lab, and the price structure within the individual practice. I would not necessarily go to the "cheapest" dentist. Please seek reviews from friends or online sites. Good luck.
It varies. Veneers, when done by an experienced cosmetic dentist, will close most spaces nicely. It generally takes at least 2, but if the space is quite wide, it may take 4 veneers to make it look nice. The fee is not less than $1400 and generally closer to $2, 000 per tooth.