Shop around before you buy a copy of that vital record. Experienced genealogists usually know where and how to get the best price on a vital record, but those who are just starting their ancestral search may pay significantly more than they have to.
Generally speaking, copies of birth, death, and marriage records are best ordered from the local (county or city) office that records and maintains them. Additional copies of these records may be at a state department of vital records, but typically their prices are slightly higher than local offices. Of course, there are always exceptions.
In some cases, the records may have been microfilmed and may be available at either a state archives or via the Family History Library. In some states the records have actually been placed online at no cost. This is true for at least Missouri, Arizona, and Utah for some records in some years.
It is never cheapest to order from one of the "online providers" of vital records and genealogists rarely need "immediate service" which significantly adds to the cost.
Before you purchase a vital record for the first time, search the UsGenweb page for the county where the event took place. These pages may have information on obtaining vital records for the county in question. If that does not work, consider posting a message to the appropriate message board at rootsweb http://lists.rootsweb.com or http://boards.ancestry.com. Someone may be able to tell you where to obtain records for the place in question.
Don't just type in "kansas vital records" into google and click and buy at the first site that comes up. Save that money for other copies ;-)