Use Newegg coupon code EMCPGPF95
Newegg has this Rosewill 3-in-1 Metal / Voltage / Stud Detector for $9.99. Use the coupon code and the price drops to $6.99. This 3-in-1 detector features an LCD and audible indicator. It requires one 9-volt battery, not included. Shipping is free.