Mo. Rev. Stat. § 141.190

In all counties of the first class, except counties of the first class not having a charter form of government, attorneys' fees in the sum of ten percent on the amount of money actually collected and paid into the county treasury shall be allowed; provided, however, that in each case a fee of forty cents may be charged; and provided such fee shall be collected on all delinquent tangible personal property tax, and such fees shall be taxed and collected as other costs and penalties and shall not be deducted from the tax. All fees herein provided for shall be accounted for and paid to the county treasurer for deposit in the county general revenue fund as otherwise provided by law.