bro Fallen..I recommended Sammy hotel because you asked for a 3-star hotel. I actually came back from a holiday 2 weeks ago so I can give you
Abit more info.
You can try Phung Ha hotel. It's a small girl friendly hotel , a stone throw from the beach. The staff is friendly and the rates start at vnd600,00 for a room with a beach view. Take note that the room rate is 50% more on Friday and even up to 100% more on Saturday . Reason is a lot of saigoneses come for weekend retreat.
Next to the hotel are little cafeterias for food and drinks. To go pubbing or seafood joints or other places of interest take a cab. They go by the meter and there are plenty on the roads.
Bro Woo..we booked a taxi from HCM to vungtau for vnd1.1m for the 2 hour journey. Negotiate the fare before booking.
Hope this helps.