OP, have you checked the requirements listed on their website?

http://visa.blsindia-usa.com/howtoapplyvisa.php

Select the type of visa you are applying for and then click "Requirements" -- for example, if you are applying for a Tourist visa, you will also need something that provides proof of address. Acceptable forms of proof of address are also given. Different requirements apply for different visas as well.

Forms of payment are listed a bit lower down on the original link. It looks like cash is accepted.

If you are still unsure, contacting them by phone/e-mail to confirm would be a good idea.

http://visa.blsindia-usa.com/contactus.php

Since this transition is still relatively new, it would be nice if you could follow-up with a short report of your experience. Thanks!