There is a small ciga factory in Trinidad and an official tobacco shop where you can buy cigars.
In the street you will find many jineteros offering you to buy their cigars which are much cheaper than the ones in the shop.Even your casa owner will probably tell you he know someone who works in the factory and he can have cheap cigars.
Some of these stories may be true but as most of them are for sure false, I would not risk if I do not trust the person selling the cigars.Infact it's true, people woirking in the factories can have a small amount of cigars for themselves to smoke but sure many of the cigars sold on the street are fake.25 Cohiba original sold in the shop cost more than 150 cuc and in the street they give you 25 for 30, the differenmce is a bit big.
Tourists often are in Trinidad for a short time therefor there are many souvenir shops. Try to avaoid them. The prices are ridiculously high and their goods are not very authentic.
Unique Suggestions: If you only have a couple of hours in Trinidad, don't have time to go to the market and absolutely MUST have small souvenir, you're still better off not buying at the giftshop!! In the end, there is nothing in those shops you won't find anywhere else in Cuba.
Fun Alternatives: The best souvenir you can get from Trinidad is a good picture of this beautiful town!
Be aware of artists you meet. They will befriend you, show you their works and have you buy one of their paintings for a huge amount of money. They promise you to bring you a certificat for the painting the next day. All the people I met with this story never saw the artist again!