The answer will depend on where in the world you are, how complicated the rail is, whether you require metallic paint or wood etc. None of this information is provided and so the question cannot be answered.
how much to caulk floor joints per linear feet
Every 9 inches of a roll with a 12-foot width is a square yard. This means every lineal or running foot of 12-foot wide carpet is 1 1/3 square yards of carpet. If carpet is $11.26 per square yard, a running foot of our carpet on the roll would cost about $15. The actual answer is $15 and 1 & 1/3 cents a lineal foot.
This can not be answered without more information. You need to know the width of the item being measured by length (which is what lineal foot refers to). If it is a roll of carpet 25 feet wide, you would need 100 lineal feet to cover 2500 sqare feet. If it is a 2.5 foot counter top, you would need 1000 lineal feet. Divide 2500 by the width in feet of the material being measured and you will get the number of lineal feet required.
The answer will depend on where in the world you are trying to buy it, and the design of the fence: joinery, height, etc.
what is the answer
That would depend on whether you had to pay for paint, how much paint costs, how many coats you need to give it, and how fast you can paint. If I have to buy the paint, I would ask at least $200 to give it one coat of cheap paint, with no guarantees.
it all depends on how expensive the paint is
Approximately 4 gallons.
Not enough information to answer this question! anyway, It's usually not priced by the sq ft, but by the lineal ft. In Nevada for the 3 or four inch paint grade base the piece price was about 6 to 10 cents per foot. for stain grade base the price varies widely depending on the height, type of o.s. corners and many other factors. The price can vary from 6 cents per foot to well over a buck a foot.
Probably between $2.50 and $3.00 per square foot
Depends on the quality of the paint. To estimate the cost per square foot, divide the cost of the paint by 350, for square meters, divide the cost by 32.5 and that should give you a pretty good idea of what it will cost for one coat of paint.
0, because a lineal meter has an area of 0