There numerous shops everywhere, almost as much as massage parlours!
I bought mine i think in chardoen or something, big chain.
Very important! The prices you see are not netto-prices in these shops! In this chain, when I complained, it was still expensive, I got a huge discount !
For hotels, check websites, like "sawasdee.com". Be aware that this period is busy! Also are you sure you want to be in 3patong", it is not everybody's cup of tea.
Kata is much nicer, and has still enough variety, to amuse yourself, without the noise and smell of Patong! It is only 20 minutes away, but another world!
Wish you "good luck" on your trip!