We stayed at a hotel right across the street from Buddy's Cafe and Ice Cream on (28) Nguyen Trai street in Duong Dong. Can't remember the name as we were only there two nights (all that was available). Buddy's is a good place for a meal or a beer (or ice cream). Since we were with family, the two old ladies were not interested in the beach. We did go to a beach on our tour, but like most we sat in the shade, drank coffee or beer, and looked out at it. Frankly, from what I could see on the tour, Phu Quoc's beaches OK to good, but not all that great. We have far better here in Florida, and they certainly can't hold a candle to Nha Trang and its island beaches, or the beaches above Nha Trang along the Khanh Hoa and Phu Yen coasts.
Our hotel was acceptable. I believe we paid close to $25-$30 a night per room. On the plus side for Duong Dong, the night market was popular and within easy walking distance. There's was a sidewalk coffee kiosk a block away on Bach Dang street, where all the fishing boats are parked, and two vegetarian restaurants, one towards the end of Nguyen Trai street (Le Loi?), and one up on Ly Tu Trong street around the corner from Nguyen Trai. The girls were all eating vegetarian, so we got to know those fairly well.
There were some hotels, restaurants and guest houses along 30 Thang 4 (30 April) street near the Vietcom bank that looked in good condition and inexpensive, but none of these were near a beach. If you want beach near your hotel, you'll have to look along Tran Hung Dau road which feeds into Duong Dong.
Beware of the cultured pearl outlets. None of the salespersons could give any idea of the thickness of the nacre covering the beads, which is exactly what determines the quality of cultured pearls. Also, none of the people working at any of the 'factories' could tell me who seeded the oysters. (Hint: Likely not Vietnamese, and most probably workers from Japan brought in to do so.) My wife purchased some cultured pearls in Broome, Australia, in 2002, and the workers in the Paspaley operation were well aware of who seeded the pearls, the most important step in producing cultured pearls, and how much they were paid per day, and the sales personnel well-versed in the thickness of nacre covering the beads in the various grades of cultured pearls. In the three Phu Quoc pearl operations we visited, no one had those answers. So buyers beware.
Oh, we traveled by boat from Rach Gia, a three hour trip, but pleasant once you fought your way on board. Also, don't waste you time on the POW Prison Compound. It seems to be a mandatory stop on the every tour. The 'tiger cages' they show you were common in ARVN camps too. Troops who committed infractions ended up in them for a few days. Unless you are into the history of obscure military disciplinary practices, you'll be quite bored, and lose some of the time you could have been on the beach.
Hope you enjoy your trip. Everyone in our gang did.