Before You Go Any Further …
You've already discussed the budget and organized yourselves — now, try to do some research —
You shouldn't assume that because a company has not had a formal complaint lodged against it that it is a reputable business (your complaint may be the first), nor should you assume that a company with one or two formal complaints is disreputable (not every customer is sane and rational).
Word of mouth — if you can find it, and especially if it's from a source you happen to trust — is a great indicator of a business's true colors.
Stand Your GroundAvoid giving in to high-pressure sales pitches. In the end, this is a business deal. You are paying these people to perform a service for you; they are not doing you any favors by taking your money, even if they present the situation in this light. You may feel squeezed by certain vendors; take your time in deciding what's right for you and your wallet.
What will you do, for example, if you're meeting with the hottest band in town and the leader tells you that there's another couple interested in the same date you're thinking about? And this other couple is going to call him later in the day to book the band? What you're not going to do is beg
Being pressured into something may cause you to second-guess your decision. If you and your bride have already decided that booking this band is your top priority, you obviously won't hesitate to sign on the dotted line, but if pressure is the selling point, think twice.
Before you sign any contract with a vendor, read it in its entirety — yes, including the fine print. (You'll find the most interesting reading in those teeny little words.) Don't accept your caterer's word as Gospel Truth when he nonchalantly tells you that it's a “standard contract.” Make sure that it doesn't include any clauses that favor only his business in the event of an unforeseen catastrophe, for example.
Look for a clearly stated contingency plan (for example, what happens if your DJ falls ill the day before your wedding?). Do not sign or hand over any money until you are satisfied with the terms of the contract. And if you can't come to terms with a merchant, keep looking. You'll save yourself a lot of grief if something should go awry.
Remember: Contracts always favor the merchant more than the customer. That's the reason for their existence. If the contract in front of you favors the merchant in a wildly unfair manner (if the contract states that the vendor shall receive full payment even if they go out of business before your wedding date, for instance), think twice before signing it. Obviously, if this is the reception hall you've both wanted for years, you're going to jump through hoops to book it. Just be careful. Don't be so blinded by your wedding fantasies that you lose your shirts in the process.
No matter how friendly the interviewee seems, no matter how cooperative, insist on seeing the refund and cancellation policy in writing —

