I make my own (oven-dried though) because it's pretty pricey to buy at gourmet store.
What you have to invest is time though. It takes 8-10 hours to roast in oven!!!!! Usually I roast way many in 1 time to save energy.
Roma tomato works well, but the size of cheery tomato is also good that you could have a whole piece to serve.
Just halve tomato, and put them on baking pan with flesh side up. Sprinkle lightly with olive oil, salt and pepper.
"Dry" in 200F preheat oven until tomatoes are shrivel, leathery, dry and deep red (not dark), around 8-10 hours.
Store the dried tomatoes in an airtight jar and cover them completely with olive oil. This specific oil is flavorful for salad too after time.
The tomatoes dry at varying rates. Remove those that are done. Some may take a little longer to dry. But it totally worths it!