Unforutnately, like many things, it depends. If you are routing directly from your receiver to your speakers and you have a powered sub connected via RCA, then yes, you need 14 pairs. However, if you connect via in-wall cabling, you'll need twice as many. 14 pairs to go from the receiver to the master wall plate and then 14 more pairs to go from the sattelite wall plates to their respective speakers.
I bought the type linked below. I've been very happy with them, but others may recommend more secure types. Buying online will save you a ton of money.
For only $6.01 each when QTY 50+ purchased - 5 PAIRS Of High-Quality Copper Speaker Banana Plugs - Closed Screw Type