Rocket Lawyer follows a simple tenet of these sites: Offer free or low-priced services. For a subscription fee of $40 a month, users can work through an array of personal and business legal documents on their own. If questions arise, a lawyer can provide answers online.

Actual time talking with a lawyer who can advise them based on their location and type of question is billed at an hourly rate, and members receive a 40 percent discount.

“We want people to take advantage of an attorney when they have more complex needs,” Mr. Moore said. “There are times you can treat yourself for a simple cold with over-the-counter medication. There are other times when you have appendicitis and you should go see a doctor.”

Another competitor, LegalZoom, bundles conversations with a lawyer into annual packages. Its estate-plan bundle, which includes a will, a trust, a power of attorney and a heath care proxy, costs between $149 and $349, but includes a year of access to a lawyer without an additional charge.

Chas Rampenthal, general counsel at LegalZoom, said most people would never need to consult an expensive lawyer. “The $1,200-an-hour person is solving complex multijurisdictional tax plans,” he said. “You can find a competent estate planning attorney who will charge $200 to $250 an hour.”

Beth Wolfer, 55, a single mother of three in Salt Lake City, said she needed a will that cost less than that. After testing out various online sites, she settled on FreeWill because as a fund-raiser for Best Friends Animal Society she wanted to offer it to donors as a way to raise money.

Ms. Wolfer said she finished her will in less than an hour, and then had it signed by three witnesses and notarized. Instead of putting it in the vault of a law firm, she handed copies to her daughters and the charities that would receive money upon her death.