Step 3: show your wife the metal detector, and withstand whatever scolding you get from her… Say things “you’re right dear. I’m sorry dear. I don’t know what I was thinking dear. Because I was stupid, dear. I’ll make sure not to waste that much time dear…. Don’t worry dear, it’s more as a joke dear.
Step 4: wait a few days and say you’re going to the beach for an hour to exercise, because you’re trying to lose weight…and then go play with your metal detector for a few hours….
Step 5: when you come back home, before she has a chance to get pissed at you for being at the beach for a few hours jerking around with your metal detector… in the happiest mood say “Honey, honey. I’m sorry I’m late, but I was at the beach playing with my metal detector, and look what i found with it!!!!” And quickly pull out the thing you bought in step 2 coverd with wet sand and show her…
Even if she doesn’t believe your bullshit, if you remember to do step 2 each time after you do step 4, you’ll be fine so long as each time what bring back in step 2 is better than what you brought back last time… As a rule of thumb use this simple formula to guide you:
$J(new) = $J(old) * 2
Which is why I suggest you start your first step 2 $J(first) around $500.