Inexpensive speaker cables

Belden zip cord of appropriate diameter

after that, get something you can return and have a friend substitute it in (or not and tell you they did) in a double-blind test

you will be unlikely to hear a difference and if you do it will be different but not better

Belden 5T00UP from https://www.bluejeanscable.com/store/speaker/

If you would appreciate a free audition, here's another vote for Clear Day cables. You will not find a better person in audio to deal with than Paul. 
For amazing value look on E-bay for the vintage Western Electric 16 ga. You'll find the genuine article available from tajacobs. 
Best value that's new and similar to the WE would be the Duelund DCA16. Parts Connexion has it in stock now.

Good luck

that looks pretty good - breaking corrosion at the connections when removing/reinserting cables is often responsible for some of the difference in sound people think is due to a new or different cable