Good question. Every county recorders office has a fee schedule which dictates how much it will cost to file a lien in that county. So, to determine how much it will cost to file your own lien, it might be helpful to contact that office and ask what their recording fees are for mechanics lien filings.
However, third party services that assist with filing mechanics liens - like Levelset's retail option - will typically be a bit more expensive than filing a lien yourself. Currently, it costs $349 to file a mechanics lien with the help of the Levelset platform, and you can get that process started here.