by far the biggest cost with composite repairs is the manpower factor, traditional metal repairs are pretty straight forward, remove fastners, make a doubler/doublers/hand form part, paint it, re-install.
as for composite panels, sand off paint, sand out damaged plies, make a mould in some structural cases. prepare surface (the most important part) with MEK or similar degreaser/solvents, prepair repair plies, lay up repair/ mould new part, then cure the whole lot,(24 hrs in most cases alone) then sand flush/finish, then paint, all this while in full PPE, suitable workspaces, ventilated areas, etc etc. complying with OHandS and toxic hazardous materials