Hi Rosel, I usually plan my travel on my own. I have gone for packages but never liked them much, in that, it restricts my choice of hotel, travel itineraries etc. Thailand is not an expensive destination at all and you can find some very beautiful hotels at a price that may look like a steal, esp for Krabi. I'd suggest look for the hotels and itinerary on the net. If you are not comfortable with what you see, then go for package. Happy travel!
Your flights will cost you 16k to 18k (return) per pax. rest hotels or resorts 3* will cost you around 2500 to 2800 per room per night. apart from this in phuket you can enjoy phi phi island or coral island + Phuket Fantasia show (that is best and costly show around 4500 per pax) in krabi same goes for hotels and go for KRB 4 island tour also enjoy angthong national park that is a marine park will cost you around 3200 per person on seat in coach basis. i work for Thailand Tourism. in case you need any help while planning your trip reply here. :)
I have just visited Phuket and Krabi last month and would suggest to plan it yourself. We stayed 3days in Krabi and 1day in Phuket.
- MMT packages are good for places like Andaman but Krabi and Phuket is doable on your own plus you can plan or skip places or visit at your pace.
- You can rent bike for covering nearby places or book cab (bit costly but you have option to explore places on your own).
- Krabi was cheaper than Phuket so if you want to do island tours better to do it in Krabi.
- Phuket is better for night life, shows and leisure. Regards