Letter of Guarantee for Residency Visa (Dominican Republic)

I understand the the Residency process is a two step process where first you apply for a provisional visa and after a year you can apply for a permanent visa which I think is good for two years.

So I am learning that part of this is a Letter of Guarantee , by a Dominican citizen, who agrees to assume financial responsibility for any issues you may cause. Not sure if I worded that correctly. I understand that an employer can do it and I believe that law firms can do it as well though I would imagine they bill significantly for that type of coverage.

Can someone please explain to me how this works and what the least expensive, most reasonable way to go about this is for someone moving to the D.R. who is not connected to an individual citizen or company???? I am trying to research and write an article on this topic.

Thanks again... Randy