when you come to Thailand it's just the same as in every other country. 
You have to live by the rules of the country you visit. 
there are foreigners who think that they can do what they want because they are on Holiday. 
STOP here you go wrong, Thai people accept alot, but they have limits to. 
Things like drugs are not allowed so please leave it at home or not buy it in this country ,the penalties of drugs use or posession are very high ( jail ). 

When you live by the rules you will see that you have a wonderfull holiday in the land of Smile. 
there are many restaurants and places to shop. 

If you are in Bangkok you can visit 2 places where you can buy cheap clothes,food and many other things. 

1. JJ market or Jatujak market . a big weekend market with hundreds of shops.
2. Suam lum Night bazaar . every day open go in evening they have a food court with nice place to sit      and live music .generally they show soccer on the big screens. 

If you have the time travel all around thailand by bus, train, tuk tuk or even backpacking. 
you will see all the beauty Thailand has to offer. 
make sure you have always enough water with you and something to protect yourself from the sun. 
you don't want to end up in a hospital on your vacation. 

I first came to Thailand as a volunteer . I worked as an english teacher at a local school . 
in the vacation we had from school i explored Thailand as much as i could. 
if you are Young and want to taste some real Thai culture come as a volunteer and work in a program with a company that helps you with your stay here.The company that helped me with my stay here did a wonderful job .People are kind and speak very good English.Any places where you want to stay they will try to find it for you. 

If you want to try being a volunteer visit theier website. Teaching&projects abroad. 
 

Do and don'ts read in link left menu.