If you have a simple situation -- married couple, children belonging to the two spouses, no property owned jointly with other family members, no trusts, etc. -- you can get an inexpensive will.
Be prepared to reconsider your will every couple years. For example, if we'd both died when our children were toddlers, it'd be completely reasonable for the guardians to have received the life insurance, profits from your house, etc. But if we both died now -- now that we have a high school junior and a college student -- I'd want the guardians to receive some money to "finish" raising our high schooler, but I'd want the kids themselves to have the bulk of the money -- but perhaps with some strings attached so they couldn't go out and buy really nice cars and then be unable to pay for college.