Does anyone filed a provisional patent without a lawyer?

If you're good at writing patentspeak, using LegalZoom is a fine way to go. But if you have them review your text, it will get more expensive.
The purpose of a provisional is to set a date.  You mainly need to make sure you identify what you're claiming so when you write the actual patent (within a year) you can get the earlier date. Provisionals are not reviewed by the PTO, but they would be part of litigation later on, so its' a good idea to be thorough but it doesn't have to be patent speak.