Air-tickets are up to you. We recomend to look for air-tickets on web site like www.kiwi.com or www.skyscanner.com but to buy it is better and more save on web site of concrete airlines. If you don't have experience with buying air-tickets on line, contact us and we will do our best to help you. Specially from USA we can arrange them for you throught travel agency. The higest prices of air-tickets are from December till April, it is high season in the Dominican Republic.
Right now there is not any obligation because of covid. You do not need the test or vaccination, you just fill in on-line form: https://viajerodigital.mitur.gob.do/