You can acquire a Toll-Free number for $3.95 with a per minute rate of 2¢ – 23¢ depending on the origin number. You could do a vanity lookup with help from support, but you would be charged a larger fee if they find the number you would want. This is in addition to the setup fee, and a prorated monthly fee for the telephone number.
If you wish to get a number that is local to a particular area, this would be $6/month for unlimited incoming calls. This also includes a higher setup fee which is charged at time of purchase in addition to a prorate of service. If you want multiple phone numbers, you can set the numbers to ring other extensions, or even go straight to voicemail.
Most people in the US will have unlimited domestic calling to any number in the US. The need to acquire additional telephone numbers isn’t a requirement. The number that the provider gives you will be enough for people to reach you.