Eastwood offers its Eastwood Rust Encapsulator 15-oz. Aerosol Can in Black, model no. 14741Z, for $16.99 plus $5.76 for shipping. That's $3 off list, tied with our mention from three weeks ago, and the lowest total price we could find. This epoxy-fortified encapsulator covers about 10 sq. ft. and is designed to stop surface rust from spreading.
Of note, it's also available in Red, model no. 16040Z, or Clear Matte, model no. 14819Z, for $16.99 plus $6.46 for shipping.