Adorama has four different Manfrotto filters as their Deal of the Day for up to 90% off.
Manfrotto 52mm Essential UV Filter $1.95 (Reg $19.99)
Manfrotto MFADVUV-55 55mm Advanced UV Filter, 12 Coating Layers, Anti-reflective Coating, Water Repellent $7.95 (Reg $33.99)
Manfrotto 77mm Advanced UV Filter $9.95 (Reg $54.99)
Manfrotto 82mm Professional Protect Filter $19.95 (Reg $89.99)