Depends on multiple factors. We did Bangkok, phuket, Phi phi and Krabi in 45k per person in Jan-feb this year for 7 days. You can check out our itinerary on our profile.
Depends on when u wana travel. i did a 10 day thailand trip on 70k including luxury stays shoppingand everythng. early booking of flightsform skyscanner, booking airbnb in bankok, agoda or booking .com for huket krabi etc.