Total expense would be around 1.5-2L You can book villas on airbnb..a one on a hill will cost cheaper compared to beach hotels..the villas are very private and comfortable..just check reviewsbefore hand and have all the facilities including swimming pool,kitchen(oven,refrigerator,cookstove etc) Seychelles is expensive in terms of food and carry some ready to cook stuff like mtr mixes and you can cook them in the kitchen of your villa and this way you will save a lot of money otherwise a meal would cost around 8k..Also you can book car in rent for your entire trip.this will cost you around 10k excluding petrol.When you have your own vehicle then you may roam around any where at your comfort. Shopping in sychelles is very expensive as well and they take only cash in local market so in case you want to shop carry cash in their currency with you.So main thing is Food & vehicle if you save on these two you can enjoy your entire trip without overburden of expenses