If your family is in town, I don't think embalming is even required, unless it is a legal requirement. Have a viewing at the funeral home in a borrowed casket and then cremation. Or choose a less expensive casket. I remember when my mom passed the funeral home had fabric covered cardboard caskets that were simply made but nice.
Besides the casket there are transportation fees, fees for the vault, opening an closing the grave, the plot itself, a headstone or grave marker, etc. It can all add up pretty quickly but there are inexpensive options. People probably spend more than necessary out of a sense of guilt or trying to impress other people. It's probably a good idea to at least do a little research on these kinds of things before that unfortunate time, and to take a third party with you to help you make rational decisions. It can be an extremely difficult, emotional time.