Next to Sri Takua Pa is the new city – which is just like almost any other city in this area of Thailand. A few houses along the road, a few small shops, restaurants and a market. So nothing special and nothing that you need to visit.
However, when you go to Sri Takua Pa anyway then you might as well go back home via the new city and visit the small market.
It has a range of stalls all selling meat, fish, fruit, vegetables and typical Thai snacks (nuts, crackers, sweets). The prices will be cheaper than in the tourist centres such as Bang Niang or Khao Lak but the offering will be pretty much the same.
So if you are looking for cashew nuts, dried banana chips or Thai curry pastes to bring back home, you might as well get them from this market – it’s easy to find as it is next to the bus terminal. There is also a cooked food market if you’d like to have a snack.