Nanita,
First, welcome to DR1!
The general advice on this board is that it is usually best to come down for as long as you can comfortably afford, and try various places out. People who "had" to live right on the beach now are much happier somewhere in Cibao, where the temperatures are milder and they can get to an actual mall with a movie theater in minutes. Others move out of the big cities into the campos.
The point is, what you think you want prior to arrival may be very different from what actually makes you happy. To figure that out, you need time and patience.
In DR, it is incredibly easy to buy and exceptionally difficult to sell property. Rent until you're sure, then rent some more.
It's best to take between six and twelve months to learn the lay of the land prior to opening a business. If you want to teach classes, do it for someone else. Yes, there's next to no money in it, but you'll learn how the business works in the DR context (which can be very different from what you already know.) That will help increase your odds for success when you finally step out on your own.
It's great you have an online business. Most non-pensioner non-financially independent folk don't, and all too often find there's way too much month left at the end of their money.
Once you figure a realistic budget, double it for at least the first year. In addition to your initial set-up costs (furnishings, transportation, etc...), you'll initially be tempted to live in a semi-touristy manner, which can be expensive. You'll also make rookie mistakes (and will be taken advantage of a little bit), so you need to plan accordingly. You'll also find yourself fiending for something that reminds you of home, which often manifests in unplanned trips back home, or unnecessary visits to IKEA, or expensive meals at whatever fast-casual spot you probably didn't go to that much back at home.
No worries, whatever you don't spend will still be there after the first year.
Either way, good luck!