I am not into cost issue, but it appears to me for a blind person, any visual input seems a benefit.... Sources to check are:

• EpiRet III Implantat, 25 Channels, Uni Marburg

• Boston Retinal Implant, Bionic Eye Technologies, Inc. and Visus Technology, Inc., subretinal implantation

• Pixium, 49 channels, former Stanford Optoelectronics Group, now Intelligent Medical Implants

• Nidek Multichip, 64 channels 

• Osaka Implant, Dept of Visual Science, Uni Osaka, trans-choroidal stimulation

• „Phoenix 99 Bionic Eye“, Bionic Vision Australia, in collaboration Cochlea Limited, sub-choroidal implantation

• Retina Implant AG and Prof. Zrenner Tübingen: http://rspb.royalsocietypublishing.org/content/280/1757/20130077

• and of course the commercially available Argus II by Second Sight.

Please post when you learn about pricing ;-) 

Recent era, Bionic Eye or Eye Prosthesis related R&D activity accelerate...

Some link are represented below may useful.

http://www.ncbi.nlm.nih.gov/pubmed/24526779

http://www.theatlantic.com/health/archive/2014/08/a-bionic-eye-that-restores-sight/378628/

http://www.medicalpracticeinsider.com/news/bionic-eye-selected-top-medical-innovation-2014

I have also initiate with this interesting topic and published couple of papers. 

But,it mainly related with Control Modelling. 

The main briar regarding this research issue to interpret EOG signal. 

 http://link.springer.com/chapter/10.1007%2F978-3-642-31686-9_19

http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=6146865&matchBoolean%3Dtrue%26queryText%3DNeogi.B

Thank you....