My first machine was a Bounty Hunter 2200. It came from Walmart. It says on the box that it will pick up coins at 10" down. I air-scanned a shovel, a pick axe, a quarter, a car axle, and even my Nissan Maxima.... NOTHING and I mean NOTHING would register at over 4" away. Not even my CAR!!! I found a few good items in my yard, and took it back to Walmart for a refund, till I got lucky and stumbled onto 2 free Garetts. (Thank you Jesus!) My GTA Ultra 1000 will pick up a dime at like 10" if adjusted right.
Maybe theres a good point to all those el cheapos out there. The cheap MDs will help weed out a lot of possible prospectors. I talk to people all the time who have a BH or a Micronta. They have it in their closet, buried. They wont sell it, but they havent used it in 8 years. The reason is they get tired of digging junk. Its there in case they lose an earring or ring... or maybe some day they'll go digging. Or... I hear this a lot... they might take it to the beach once every 5 years.
I buy them at flea markets for spare detectors for the other vehicles. The next BH I find for $15 or so will go in my plumbing van so when I spot a good site between jobs I can have a lil fun. I want a 5th one for my other van. A cheapie is better than no detector at all.