I would very highly recommend sticking with professional cargo shipment services like FedEx or, my preference, DHL. It will be expensive, but I highly doubt it would be more expensive than that and even if it is, you're getting a much more reliable service.

I would also very highly recommend having a firm grasp on DR customs. The Dominican Republic is not a carnet country, so the importation of professional goods, electronics equipment, samples, etc becomes a very time consuming process. While I've never shipped to/from the DR, I've heard some horror stories from people who have and had DR customs impound their gear for months at a time or force importers to pay a huge deposit to make sure every piece of gear brought in gets taken out.

If you're just shipping smaller things like items to start up an office, it shouldn't be an issue, but if you're importing high value items like computers or camera equipment, you're going to run into some issues. The DR is very much on edge when it comes to electronics being brought in so you'll want to cross all the Ts and dot all the Is. I've heard some absolute nightmare stories from film crews trying to get into the DR for a shoot. Depending on what and how much, how often, you're shipping, you might want to consider a third party company with experience handling customs in a place like the DR and/or have a local fixer on that end to help walk your stuff through each step of the process.