The business answering machine greeting you use should be fairly short and to the point, though you can use it as a way to demonstrate what your business has to offer. Your overall tone in the message should be professional and indicate to callers that though their call has been missed at that moment, they are important and you plan on contacting them as soon as possible. Within this, however, you should not indicate that you are talking to someone more important than the caller. Your business answering machine greeting should also be customized in any way you deem appropriate for your business and needs. Jotting down the greeting will prevent mistakes when recording it.
Yes, you can be charged. This depends on the service. For example, Spectrum’s Voice Residential Services Price Guide charges $3.95 for voicemail.

In Australian English it’s pronounced with the vowel /a:/ like in ‘part’. Problems arise when people use the /ʌ/ vowel (like in ‘up’) instead of /æ/ or /a:/. If you do this is will sound like the worst swear word in English. Many non-native speakers often pronounce the vowel /æ/ more like /ʌ/ because they don’t have a vowel like /æ/ in their first language. Many speakers of European languages will do this (Spanish speakers and Italian speakers) and also speakers of Japanese and Korean. This problem with /æ/ also means that if you say the word ‘back’ in your voicemail greeting sample, you are likely to pronounce it more like ‘buck’. remember to pronounce word endings in English. Check you aren’t dropping any endings off or mispronouncing them.
If you are a burglar, then we’re probably at home cleaning our weapons right now and can’t come to the phone. Otherwise, we probably aren’t home and it’s safe to leave us a message.