Cecomsa? Ceducomp?
I've dealt with Cecomsa, Santiago, for a number of years. Exc. customer service & reliability. The prices of its clones are only slightly higher that the US. If you live in POP, going to Santiago for service gets to be a nuisance. Ceducomp, Puerto Plata, is also very reputable. A very competent collection of young Dominican technicians.
Used?? Proceed with extreme caution; swapping parts & skulldugery is extremely common here. LISTIN DIARIO? Try its Classififed section. Some shops in Santo Domingo advertise rock bottom prices; I've had no personal experiences with them? Also, indiviudals sell fairly new computers. If you buy used, I suggest you stick with a name brand, not a clone. Dell, Compaq, & HP [to name 3 of probalby severel] can be easily repaired in the DR, usually in Santiago or the Capital. Food for thought? If you're coming from the US, why not buy a brand name in the States, bring it in your suitcase in the original box; then, buy the monitor here? Good hunting.