I've been travelling for long and thus manage everything myself. Cost depends on your own choices. For two week holiday in Thailand (7 days in Bangkok and 7 days in Phuket), it's approx Rs. 200,000 for single traveller. Includes air ticket, hotel, food, taxis, bike rental in Phuket island, entertainment, etc. excludes shopping. You can spend a lot on shopping though. huge variety and unique products.
Yes I stayed near Patong beach. It's a busy beach and shopping area. Arabic, Indian food places, etc. I like quiet beaches so in the day time went to Karon and Surin beaches and spent some quality time there. Nai Harn and Prom Thep cape beaches are also nice. Some beaches are on private property. Like you have to pay to enter them. Distance in 15 to 20 km away from each other. So you rent a bike and go as you like. Petrol is Rs. 120 ~ 140 per litre and available at shops everywhere on the island. A one and half hour trip to Phi Phi Island is a must. Boats go from Rawai beach pier.