Hi Alex,
Welcome. First, I urge you to visit Brain Godwin's website on early English locks. Just Google "Brian Godwin English lock". His site will help get you started with understanding the evolution of flintlocks in England. When you say "flintlock" you want to make sure of what you are searching for. The true "flintlock" has the battery or steel attached to the pan cover to form what we today call a "frizzen", it has a vertically acting sear with half cock and full cock notches in the tumbler, and all of the working parts except the flintcock, frizzen and frizzen spring are completely internal. The true flintlock was invented in France between 1610-1625. It eventually began popping up on English guns about 1650. There were other flint-using locks that predate the true flintlock. The snaphaunce has a separate pan cover and battery, and a lateral sear that protrudes through the lock plate to catch a lug on the back of the cock and hold it at fullcock. When the trigger is pulled the sear bar withdraws into the lock releasing the cock, which holds a flint. As it moves forward a pushrod within the lock plate pushes the pan cover forward, exposing the priming powder. Snaphaunces may be as old as about 1550 and were used in England during the end of the 16th and beginning of the 17th centuries. The English modified the snaphaunce by combining the pan cover and battery into a frizzen but kept the lateral sear mechanism. That modification is sometimes called the "English" or "Jacobean" lock and it was used between about 1625-1660. Brian Godwin has a lot of good info on the styles of English locks. They also made a "Doglock", which looked like a true flintlock but with an external "dog" or "catch" that hooked the back of the flintcock when at halfcock and acted as a safety device. Doglocks were made between about 1650-1730 or so. The Scots employed a uniquely shaped snaphaunce beginning in the 16th century but also developed the "Highland" lock, which was commonly used on their all metal pistols from the mid 1600s until well into the 18th century. The Highland lock has a frizzen but also a lateral sear that protrudes through the lockplate in front of the flintcock. When the trigger is pulled, the sear recedes allowing the cock to fall forward. In addition to all this, the Spanish,Portuguese, and Italians developed a flint-using lock called the Mediterranean or Miquelet lock and another unique flint-using lock was developed in the Baltic countries and Scandinavia called the "snaplock". Nonetheless, only the French-invented flintlock contained all of the features that we commonly refer to simply as "flintlock" today. You should find a copy of Torsten Lenk's famous book "The Flintlock: its origin and development". I cannot help you with cost and value because that will vary tremendously depending on rarity, condition, style, etc. I will say this, English gunmaking during the 1st half of the 17th century was far behind continental European makers. Only a few makers in England had reputations for making high-end guns, most were of a utilitarian nature. The English Civil War worsened that condition because gunmakers were focused on simple military guns and they lagged behind the technical innovations and decorative styles found in continental Europe. That changed after the restoration of the monarchy in 1660, which encouraged development of the English gun trade and also brought in a flock of talented foreign makers, many of whom were fleeing religious persecution in Europe. The English gun trade blossomed and many of the finest and most valuable firearms made in England come from the period 1660-1720 or so. Earlier English guns tend to be simple utilitarian pieces but they are very rare and probably command high prices. I think virtually all Scottish guns made between 1580-1746 are very rare, partly because so many were destroyed after Culloden. I suspect any Scottish gun from that time would command a high price. Hope this helps.
dave
