You won't be even in the $50 wire budget for all your speakers.
Banana plugs are needed if often swapping occurs between speakers, amps or wires so you can rapidly plug and unplug.
Within the time they loose stiffness of connection and become kind-of loose. In that case I would recommend to aquire only locking bananas. Bananas offer the smallest connection surface but if properly maintained(cleaned once in a while) there is just only the small compromise.
Spades are just like bananas with bigger and stiffer contacting surface. They need to be tighten up as firm as possible probably with the wrench where applicable. When I used the spades I managed to tighten them up the way I could see the squized semi-sphere trace. But than again I've come to the conclusion that I have to execise a connection with no bananas or spades and that's what I use now. Make sure that spades have the right size for your binding posts.