I want to buy a bouncy castle for my kids but can only find them in China when searching online, does anyone know where i can purchase 1, also does anyone know if you have to pay duty if it is ordered from China ?

Offer some money to those that already own them to give you their source.

Street/temple fairs rotate periodically on certain sites all over the country, four in my neighborhood in BKK, one's always going on.

Bouncy caste in Thai: บ้านเป่าลม (baan bpao lom).

You will need someone to talk (phone) in Thai anyway.

Unlikely you will find an english language for that in Thailand.

Online store (?) http://playsanook.com seems to have many.

Pictures from playsanook:
http://goo.gl/IaItP7

Pictures for bouncy castle in general:

http://goo.gl/8I7UwS

Examples (two quite big ones):

http://goo.gl/1oh3jz
http://goo.gl/cOeimT

Huge selection (seems for "professionals" like you see on the fairs as @wym mentioned):

http://www.inflatablesthai.com/

Edited January 19, 201412 yr by KhunBENQ

I bought a good one from Toys-r-us some years ago which at the time cost GBP 50 & was good for a dozen kids. I suspect China or ebay will be your answer this time.

HTH

Edit: Toys R Us TH website link added:

http://www.toysrus.co.th

Edited January 19, 201412 yr by evadgib

I love posters starting dedicated queries and not replying at all