If you are looking for an 18th or 19th century longcase clock, so 1700 through to 1899, then there were many changes during that time. At the one end of the spectrum, at 1700, pendulum clocks had only recently been perfected, and so these clocks are more expensive, and they were almost exclusively made in England or Holland at that time.
At the other end, by 1899 most English and Dutch makers had moved on to other clock styles, so tall clocks were being made in Germany and elsewhere. The fancier clocks still made in England played Westminster chimes on tubes.
Duration depends on where and when the clock was made. Most English clocks in the mid 1700s onwards were made in the country, and so were 30 hour, although London makers almost always made 8 day clocks. Month duration clocks were in fashion early in your time period, but year duration were always very rare. Month and year duration will always be much more expensive.
tell us more about what you want and maybe we can make recommendations- now is a good time to buy a longcase clock, as they are out of fashion.