What is a brand of metal detectors decent but cheap?

Recently I moved to a house that sits on what used to be only field and marsh. With my interest in the Civil War era, and knowing that the neighbors have found many elements of the soldiers in their yards began the search for a metal detector, but the problem is that I have no idea what to buy? I want it to pick up objects, both in my garden and the river at low tide, but I want something cheap, since it is a hobby for now. Any suggestions? I was looking for buttons, knives, canteens, etc.

To prove the local economy, some pawnshops have them in a wall of dust collection. If you want a new attempt on this site: http://www.metaldetectors.com/ Be careful, If you discover a lot of artifacts, the local museum be declared backyard of a historic site and lost everything. Here is a clip about it: LONDON – It is unprecedented finding that could revolutionize ideas about the rulers of Germanic medieval England: an amateur treasure hunter in search of a field farmer with a metal detector discovered a large collection of Anglo-Saxon gold and silver artifacts.

Finding Stuff With Metal Detectors