Good news and research features. When buying, commissions are in the bond's price.
Commissions are low: $3 per $1,000 muni bond. Decent screener, though sectors are left out.
Muni quote tool gives an accurate picture of the price range for bonds. Good calculator for taxable-equivalent yield.
Commissions range from $2.50 to $5 per $1,000 bond. Comprehensive screener.
Muni prospectuses and fiscal reports for $7 and up.