I would expect to pay somewhere in the vicinity of $19.99 to $39.99 depending on the make and quality of the plow markers. This is based on a preliminary search for the product by someone who is not a professional.
I have not seen any type of lighted plow markers but the standard plow markers are around $30.00 a set. They are usually red wiht Yellow caps which helps visibility.
You are looking to spend anywhere from $70-$100 depending on the store you purchase them from. j.C Whitney sells them for $89.00, but you could find a better deal Rec Stuff.