AnswerComforter sets from several stores can be offered with free shipping, like Anna's or Walmart. Sometimes the stores specify a purchase limit in order to get free shipping. Most retail stores like Sears or Walmart will offer the choice of instore pickup which will save shipping costs.

AnswerFirst of all, I always ask my friends/family who might have gone through this situation before and ask their opinions. But you can also look for clues around the house of it you need duct cleaning or not. If your house has molds, vermin, or if the air quality of your house seems worse, I would definitely check into it and call it to the attention of your maintenance provider. Here is a helpful link: http://epa.gov/iaq/pubs/airduct.html