Some hidden additional costs that might not make it into your original budget...
1) Sound Equipment
Don't ever assume that this is all covered within the contract price with your DJ or Band - basic packages include basic equipment. If you have a large space you may require additional speakers. Additionally, your venue may not have the equipment you'd prefer or only their basic equipment is included in your room rental. If the venue does have the additional equipment, it may not be included and may cost extra to rent.
2) Rental Company fees
Most rental companies have a list of things that will cause your invoice to be adjusted. Make sure you're aware of all the obstacles that the delivery men will have to go through when unloading your equipment - and I mean EVERYTHING. Stairs, elevators, if they can't park near-by, if you aren't there to recieve the order causing them to wait. Additionally, when they return to pick-up the equipment, if the tables and/or chairs aren't folded or the linen or dinnerware have food on them then you're credit card won't be sharing in on the newly-married bliss. Elevator and stair fees may cost $5 - $10 PER trip, and hourly waiting time may cost upwards of $60 per hour, per man (so think of 2 men waiting for one hour = $120).
Make sure you know exactly where and how your rentals are being delivered should you be handling this (hotels and banquet halls will have proper loading bays and probably deal with one rental company regularly) and that you read the fine print.
3) Gratuities
Make sure you know how much your caterer and/or venue charge (who ever has to hire staff) and that it's accounted for beforehand. Additionally, factor in all the other suppliers that you will be tipping and find out how much (if you aren't sure, don't be afraid to ask the supplier what is normally expected). These people could include hair stylists, make-up artists, DJ's, performers and entertainers, caterer, bartenders and other outside staff, servers and clean-up crew.
4) How is everything getting there?
A common, last-minute question you'll find yourself asking your suppliers is, "Do you deliver? How much will it cost?". You may assume there will be someone around with the time to pick-up the cake, flowers and decor - but as the day gets closer, you may realize that it's more reliable and less hassle to have the supplier deliver. Additionally, you may realize you no longer have the trunk space or the time.
