There are probably several aircraft that meet the requirement of reasonably priced 4 place aircraft, but one that comes to mind is the Jabiru 430. From what I have heard they have pleasant flight characteristics, plenty of space, MTOW 700Kg (1543 pounds), cruises at 120 knots and the kit, which is a fairly quick build and includes basic instruments, propeller and 3300 engine sells in Australia for A$87,600 including 10% GST - that's about US$63,100 on current exchange rates. All you Jabiru haters are not going to like this, but Jabiru also have a far better safety record than anything else around, including the Sonex that I fly. If you don't want to fly behind a 3300, you can buy the kit without engine for A$66,700 (US$48,050) and fork out the extra money for a Rotax. See
http://jabiru.net.au/kits/j430-kitOne Jabiru 230 builder (the 230 is just the 430 without the back seats) I spoke to told me the empty weight of his aircraft was 330 Kg (727 pounds) indicating a very useful payload.
Peter