Lol, that's a tough one to answer because "Utility" of a 3d printer can be defined differently for everyone . Anything in the Ultimaker, or Replicator price line uses is something that will give you reliable accurate prints. Sure you will need to dish out $1200-$2500 depending on the printer, but it will be money well spent in the long run.

Having said this, there are some promising cheaper printers making their way into the market. For an absolute beginner these could often be a way to get your feet wet.