The White's electronics website is a reputable source for finding their brand of metal detectors, but various models and accessories can also be found on Ebay.com and Kellycodetectors.com. White's Electronics and the Kellyco Metal Detectors websites both offer brand new models and accessories.
Ebay offers used models at lower prices, an option for those who are new to metal detecting and aren't sure if it's the hobby for them. Ebay also offers user reviews that can help newcomers narrow down what features they want their model to have. White's website also includes a search feature to find the nearest reputable dealer. Whenever possible, it's helpful to go to a dealership in person to ask questions and figure out which model is best for your needs.