Standard PCB input / output connectors/technique?
Option 1:


Solder a 0.1" (2.54 mm) male pin header on the PCB with as many pins as needed, and the cheapest female 0.1" connector you can find to connect to it.
Pin headers can be had for as little as US$0.96 including international shipping, for 80 pins, on eBay. Simply cut and use as many pins as you need:
  

"Servo cables" for RC aircraft have 3 connections, and are pretty inexpensive as well, again this one is US$0.96 including international shipping on eBay:

That gives you 3 wires, for power, ground and your signal, just perfect.
To address the question about how the connectors will stay connected to the PCB: The female connectors have a spring-loaded action inside, to grip the male pins. However, a firm tug will pull the connector off. 


Option 2: 


Use industry-standard JST (Japan Solderless Terminal) connector pairs, with the male side soldered to your PCB.
This one, for instance, is US$1.86 for 5 sets of 4 connectors each:

These have a snap-fit action in the plastic housing, hence a more robust connection than the plain pin headers.
This seems to be the most cost-effective option, if you can find some use for the other 4 connector pairs.


Option 3: 


Use one of a variety of common connectors you can either liberate from old equipment or buy dirt cheap from a local audio or electronics repair store, such as used for battery connectors or headphones, e.g. 


2.1 mm barrel jack on the wire side and its socket on the PCB side, if 2 conductors will suffice, i.e. signal and ground
3-pin (TRS) or 4-pin (TRRS) headphone socket on the PCB and corresponding pin on the wire side, if 3 or 4 conductors will suffice.



Option 4: 


Any number of increasingly esoteric and increasingly expensive board to wire connector pairs, depending on desired number of connection cycles, and other constraints such as current capacity and size. Electronic component vendors like DigiKey provide a surfeit of options.