The Jomtien Night Market sets up in a sandy lot just back from the beach near Jomtien Soi 5 most evenings from around 5pm. It is small compared with the big Pattaya markets but considerably more local: cheap Thai food (pad thai, pork skewers, papaya salad), fresh fruit, knock-off T-shirts, mobile phone covers, the usual.
The food is the main reason to go. Most stalls take orders in mediocre English and prices are clearly displayed — expect to spend around 100 baht for a generous plate of grilled meat or noodles. A glass of fresh fruit juice or a Thai iced tea is 30 baht. Half an hour will cover everything; combine with a beachfront beer afterwards.