washington u.s. customs border protection agency say friday accept proposals next month design wall build near u.s.-mexican frontier first step pick vendors president donald trump propose border wall document federal government website business opportunities cpb say would release request march ask company prototype ideas wall build near u.s.-mexican border review ideas submit vendors agency evaluate select best design march 20 issue request proposals march 24 vendors would ask price cost build propose wall document say multiple award barrier expect mid-april part process aggressive schedule government construction project go start soon way ahead schedule way ahead schedule trump tell conservative political action conference friday spokesman u.s. customs border protection speak condition anonymity say solicitation publish friday everything wall trump propose spokesman say initial request information give industry opportunity tell department homeland security oversee cbp possible construct border wall get feedback vendors look ones feasible spokesman say would follow request proposals firm exactly much construct wall would cost u.s. department homeland security internal report see reuters month indicate border wall would series fence wall would cost much 21.6 billion build take three years complete report estimate price tag much high 12 billion figure cite trump campaign estimate high 15 billion republican house representatives speaker paul ryan senate majority leader mitch mcconnell plan lay would take seal border three phase construction fence wall cover 1,250 miles 2,000 km end 2020 654 miles 1,046 km border already fortify new construction would extend almost length entire border u.s. agency seek ideas trump 's propose border wall