Pleated shades supply a certain amount of insulation, but they are not as energy-efficient as honeycomb shades. In the summer, pleated shades protect against solar heat gain, but (consisting of only one layer of fabric) they are less effective at insulating against cold in the winter.
Pleated shades run between $55 and $75 for a 27-inch window. They are less expensive than woven wood shades, but generally more expensive than honeycomb/cellular shades, roller shades, and fabric/Roman shades.
Costs vary greatly by region (and even by zip code). To get free estimates from local contractors, please indicate yours.