Yeah, it's hard to miss those three legs. The actual name of this three-legged device (so the Internet tells me) is the triune or triskellion. QUOCUNQUE JECERIS STABIT means 'whichever way you throw me, I will stand', which is the motto of the small Isle of Man located between Scotland, Ireland, and England.
Look at this well-preserved coin in the picture. The picture was sent to us from requester MadScotsMen himself. It is in beautiful shape. He also has several other examples, but this is his best one.
Don't clean your coins, MadScotsMen! Cleaning ruins value.
Here are some typical catalog values for these coins:
worn: $50 US dollars approximate catalog value
average circulated: $150
well preserved: $800
fully uncirculated: $2500
HALF PENNY (COPPER)
worn: $35 US dollars approximate catalog value
average circulated: $120
well preserved: $500
fully uncirculated: $2000
The catalog also says that these coins were minted in several different metals, and those in brass, silver, and bath metal (a form of bronze) command higher value than the normal copper pieces. Remember that catalog values are inflated values. Use the Terminology page for more information about what 'catalog' means.
Consider having your coin authenticated, graded, and encapsulated by a numismatic service such as PCGS. Once your coin is mounted in a reputable numismatic slab, it will be worth several hundred dollars more than a 'raw' coin.
By way of encouragement, Gord Nicols of CounterfeitCoins.com writes to CoinQuest:
Thanks for your kind words about my web site. I have not heard of a forgery of the 1733 coins.
I have heard that these 1733 coins were counterfeited in their day but such a counterfeit in that condition would be as rare as a genuine example.