Every state's got its own little wrinkles on that subject, so you really do need a lawyer; though your question should be a half an hour's time.
As a general proposition, most states have a 'small estate act', which if your property is worth a relatively small amount, it's easy to settle without a will; on the other hand, if you've got to worry about where the millions will be going, you definitely need a will.
If your state allows "self proving" wills, that can be useful for almost anyone, because it takes it out of probate unless someone objects. It's usually a matter of having some witnesses notarize the signatures of each other and the testator / testatrix.
In Virginia and some other states, a 'holographic' will is permitted - that's one that is entirely written by the person leaving the will holo=entirely, graphic=written. Got to be by hand and signed and dated. No further formalities are required.
Generally speaking a will is given effect even if it's not in legal form, unless someone objects.
Don't buy a fill in the blanks will at Staples, and do use LegalZoom or any other online service. You really do need to talk to a lawyer who works in your state.