I ran across an article for this- COPIED and pasted below incase you don't wanna click on the link lol: 
http://prettypearbride.com/wedding-tip-thursday-tip-your-vendors/Planning a wedding is a busy time, and for most (especially the 
brides) they are not thinking about tipping their vendors they are only 
thinking about the total cost and making sure everything fits within 
budget. I know when I was getting married I did not think about tipping 
my vendors, and closer to the wedding I was advised that it is customary
 to tip.
 While it is certainly not a requirement, but if you feel the person has done an exceptional job why not throw in a tip?
 If
 you have developed a friendship/bond with your vendors and would like 
to do something different than just adding a little something extra to 
the tab. Think about sending a thank you card with a gift after your 
wedding, flowers, or maybe even an Edible Arrangement? A token of your 
appreciation that shows your gratitude differently.
 However, if 
you just want all the wedding planning stress to be over Pretty Pear 
Bride has compiled a list below of vendors and suggested gratuity 
amounts:
 Caterer/Banquet Manager: 15%-20% is usually included in the contract. However, if it is not an extra $1.00-$2.00 per guest is suggested.
 Bartenders: Did you hire your own? Are your guests tipping? If your guests are not tipping 15%-20% is suggested.
 Limo Drivers: 15%-20% is suggested.
 DJ’s: 15%-20% is suggested.
 Bands: An extra $25 per band member is suggested.
 Photographers & Videographers: 15% is suggested. Check your contract gratuity may be included.
 Florists: 15% is suggested. Check your contract gratuity may be included.
 Bakers: 15% is suggested.
 Restroom/ Coat Check Personnel:
 Are your guests tipping? If not the host is usually responsible for 
tipping at the end of the event. $0.50-$1.00 per guest is suggested.
 Parking Attendants: If your guests are tipping then you normally don’t have to contribute. If they are not $1.00-$2.00 per car is suggested.
 Officiants:
 It is appropriate for a clergy member (priest, rabbi, minister, etc.) 
to accept gratuities or a donation along with their regular fee if they 
do charge one. However, civil officiants (judges, clerks, etc.) receive a
 flat fee and are usually not allowed to accept gratuities. For a clergy
 member $75-$100 is recommended as a tip or donation.
 Wedding Planners: Check the contract as it may be included, if not 10%-20% is recommended.