Howdy,
I am a retired aerospace engineer who had to lose weight and inches. Coin shooting at the beach does that and introduced me to a really fun hobby.
I learned of the forum when I was trying to find what I was doing wrong with a Famous Trails MD7030 Discriminator II that I had picked up at Big 5 Sporting goods. It was on sale for $99 and was claimed to be a $249 regular price. Figuring that more money was better I bought one to replace my Bounty Hunter VLF Treasure Detector ($49 at Big Lots).
I learned from the forum that there was an owner's manual that could be downloaded and a suggestion that better results could be had with proper tuning.
I did all that was suggested then took both detectors to the beach. I would use the Bounty Hunter to find a coin then see if I could find it with the MD 7030. In almost every case the answer was NO. I twisted every knob everyway possible.
I then went home and prepared some tests. The final one sealed the fate of the discriminator. I placed a quarter and a dime under 3 inches of kitty litter. The result was loud and clear with the Bounty Hunter and nothing with the MD 7030. Back to Big 5 it went.
After reading threads here and other places on the internet I now understand why.

The more expensive units have a technology to identify ferrous metals and discard those signals. The problem is that in coin shooting near salt water coins become undetectable at depths of more than 1 inch.
I search from the boardwalk to the wet sand and back, overlapping the round trip a little bit. I walk mostly on the dry loose sand to get the maximum endurance exercise. Using a simple VLF at maximum sensitivity and junk filter at minimum allows me to sweep fast in sync with my steps. I get in 3 hours from just before sunrise to 8 AM when the parking is no longer free. The result is a loss of 30 pounds and 8 inches around the waist in less than 2 months.
With the settings I can find dimes as deep as 12 inches (if flat). Of course, every kind of trash sings out as well. But that is not a bad thing for me. I have a rather large seive with the hole diagonal slightly smaller than the diameter of a dime. I have a small "super" magnet in the bottom of the basket. That stops little pieces of ferrous metal and bobby pins from dropping through. I also pick up paper trash and anything else that makes the beach less than beautiful. Each bend down is additional exercise.
Instead of paying a spa or club for weight loss training I collect "treasures". The following list is most of the treasures I have collected in the last 7 weeks averaging maybe 3 days a week. It shows what you can do with the cheapest detector on the market if you don't mind generating good karma cleaning up a beach.
Coins
372 pennies
98 nickels
194 dimes
186 quarters
2 dollars
1 wheat penny
2 Canadian pennies
1 English penny
1 Canadian dime
2 Golfland arcade tokens
1 Disney flattened penny souvenir
29 bad pennies
Rings
Large gold ring with 6 mm blue sapphire heart cut
Gold wedding band (5 mm)
Gold ring center stone gone, 2 side diamonds
Sterling silver ring (8 mm wide)
Pure copper ring with yellow stone (one ounce weight)
3 kids steel rings
Bracelets
5 chain charm bracelet with heart charms
3 miscellaneous bracelets
Earrings
Pair 3 inch gold hoops each with 60 CZ.
Pair 3 ½ inch gold hoops
Pair sterling silver with 1 carat weight CZ
Single 3 inch gold hoop
Single 1 ½ inch gold hoop
Single sterling silver with 1 ½ carat weight CZ princess cut
Single sterling silver with 1 carat weight CZ heart cut
Single 1 carat round cut CZ from damaged stud
5 single various costume earrings
Miscellaneous
White gold heart set with 16 small rubies
8 pieces various hair pins/clips with costume jewels
finger nail clippers (new condition)
toe nail clippers (new condition)
tweezers (tool type, new condition)
6 model cars
Talking Gingerbread Man (from Shrek II)
T-rex model
That may not seem like much tangible for 7 weeks (probably 62 hours) but it sure was fun, the surf/beach is a nice place to be and I don't make my doctor cringe
when I go in for an examination. There is a sleeper in the list. The 6 mm blue sapphire is worth more than $400 based on its clarity. 
I look forward to taking part in threads on this forum. It is a great hobby with lots of possibilities. One possibility is looking for meteorites. I plan on searching in the desert areas. But any tips or help would be greatly appreciated. I will read the threads to find other opportunities for treasure hunting.
Good luck and happy hunting to ALL! 
Johnj45586