i1Photo or Color Munki depending on budget.
As Alan says the default Epson profiles are pretty good for OEM papers+ink and custom printer profiles for anything else are pretty cheap anyway, so consider carefully if you really need to invest so much on printer profiling.
In terms of cost effectiveness, ArgyllCMS is as good as any other software out there and it's free (though there is a moderate learning curve and familiarity with command-line computer usage required).
The software may be free, but you still need a spectrophotometer. The most popular hardware(Color Munki & i1Pro) comes with decent supplied software that's easy to use anyway, so Argyll is a bit of a distraction in this discussion.