The costs of a catered party can quickly rise, depending on the venue, the choice of food, the variety of options and the number of people in attendance. In all of this, it's easy to forget to budget for the tip. Some caterers will include an 18 percent gratuity in the quoted price, but it's important to clarify this with the company. Even if the company does include a gratuity in the price, it's often nice to provide a little extra, especially for good service.

It's up to the host or hostess to pay for the tips to the caterer. When done as a lump sum -- such as 18 or 25 percent of the total bill -- it's assumed that the caterer will fairly divide the sum among all workers. According to Martha Stewart Weddings, though, different types of catering workers deserve different tip amounts. This includes $100 to $200 for the manager, $50 for each chef and $20 to $30 for servers and kitchen staff. Separate the money into envelopes and hand-deliver them to each worker.

In some cases, a bartender will place a "tip jar" on the bar. Guests are not required to tip for service, but may do so if they prefer. They should base this on the level of service the bartender provides them. For example, simply opening a bottle of beer might not earn a tip each time, but asking him to mix a complicated drink should get a tip.