Hi Ree
It's cheaper to buy certificates directly from the General Register Office at Southport at
www.gro.gov.uk quoting the persons name, district, volume and page numbers you find on freebmd and then checking the images to make sure the details are correct.
All these regional sites aren't complete, you need to look on freebmd or a subscription site such as Find My Past to get the registration details.
Family Search doesn't have the birth, marriage and death indexes, they only have their transcription of parish register entries for Baptisms, marriages and some burials.