i have used those cheepy one way valves any parts store have, immersed in a container of new brake fluid [of your choice].
before i put the hose on the bleeders, i wrap some teflon tape on the screw threads, and this seems to keep any air from entering the system.
gravity bleeding works sometimes as well.
a couple of years back, i bought one of those fancy aluminum hand vacuum brake pumps with all the attachments, [like my one buddy has] but i haven't had a need to try it out.
one thing i can say, if using one of those fancy pumps, my buddy says to flush out whatever metal part[s] comes in contact with dot 3 or 4 fluid, with alcohol. if you don't, the parts seem to corrode, because the aluminum [and anodizing] used seems to be of a really cheap grade. they work good otherwise.