We have a burley, we got it off craigslist, you may want to check a second hand shop too, I was in our local one this weekend and they had 7... for pretty good prices. Ours works really well, and DS really really likes it.
We have a burley solo as well. We got it from a friend who had one, but needed a double. Let people know you're looking sometimes they come from random places. Also, Craigslist is great this time of year so keep an eye out there, and jump on it, they don't often last long if they're in great condition.
Re: bike trailer