There's only one company plying Manaoag directly:

DAGUPAN BUS
(terminal along EDSA Southbound corner New York St. - kahilera nya ALPS, Dominion, Victory at SuperLines)

Basta signboard nya is "Dagupan-Manaoag" (dadaan muna sya Dagupan tapos Manaoag church next)

May mga buses sila labeled as "ORDINARY" pero aircon sya, don't be confused parang "promo" kasi nila yun, ordinary fare pero aircon amenities hehe.

Kaso you might find their stopover facilities in Tarlac not too pleasant. Its not well maintained compared to Victory Liner.

If you want better buses, sakay ka na lang Victory byaheng Baguio and get off at Binalonan (as suggested earlier)