Amazon has the Rust-Oleum 12oz Universal All Surface Spray Paint (Paint & Primer in One, Gloss Black, 245196)  on sale for $3.60 with free shipping on $35+ or with Prime (extra 5% off with 5+ S&S orders). Compare to $9.48 at Walmart, other retailers. 

• 12oz Rust-Oleum Glodd Protective Enamel (Dark Walnut) for $6.47