MK Taxi fare should be around 22,000 yen (based on my reading of the fare in the opposite direction - i.e.. from Narita to Ota Ku)
http://www.tokyomk.com/en/airport.html

Tokyo airporter purports to be cheaper than taxis but shows the same fare
http://www.tokyoairporter.com/fares.html

A company that I've never heard of before _ NL Transys is offering a fare of 20,800 (including tolls)
http://www.nl-transys.com/ticket2.html

If it's a choice between those three, I'd go with MK, which is a well known company with good quality cars and drivers.

For reference, the Limousine Bus departure at 2:40pm (from int'l term) arrives at NRT T1 at 4:15pm. To get an earlier bus, you need to take a shuttle to T2 (domestic terminal) and catch the bus from there.
http://www.limousinebus.co.jp/en/pla...ches/index/4/3