Low mass spacecraft are our only real options. A nano-sized solar sail craft powered by the sun or lasers from Earth can hit up to 20% lightspeed theoretically and its launch costs would be affordable, if not relatively cheap. We could have a spacecraft at Alpha Centauri in merely 20 years. Or simply launch them by the dozens or hundreds to various locations. Stephen Hawking has proposed this system in the past and we've had trial launches of solar sails via the planetary society and others. Its a solid and most likely doable concept at scale. Yes, your kids or grandkids will hear the results, but not you. Is that such a problem, especially when the alternatives are never launching a probe to those systems?
To be fair, the proposed Centauri mission would be within a person's lifetime. 20 years to get there then another 4 and half to get the data. So if we launch when you're in your 40s or even 50s, you'll still see the data.
We can even use this concept on heavier ships in the solar system to get to Mars quickly. How quickly? Three days quickly for a 100kg craft. This is a bit more pie-in-the-sky of course:
http://www.sciencealert.com/nasa-scientists-are-investigatin...