It's not big but there is both a commercial street and a seafront promenade in the town. There are a number of sandy beaches and the atmosphere is cosy with many good restaurants. You will feel like you have stepped back in time, especially in the low season when the weather can be quite stunning still and yet there are very few tourists.
If you like history, then the Greek temples of Paestum are less than 1/2 hour drive from Santa Maria. The town is also a good starting point for trips along the coast and into the mountains, where time has stood still for centuries. It's quiet and peaceful in Santa Maria, as the coastal road runs behind the town, and several of the roads in the centre are one way.