Farmboy is good for small purchases and prepared stuff (I find them a bit pricey but fair). I'd check T&T supermarket for other products/manufacturer.

I personally avoid most premade food like this and stick to Costco Business centre... they have a good choice in beans and lentils; if your ok with buying vegetables in bulk they have good prices on what they have (check the frozen fruit/vegetables section also, the boxes are usually 2 bags of 2kg or 4 bags of 1kg which are easier to place in the fridge). Tofu is also decently cheap at costco, 4 blocks of 400g for ~$7.

I'd also check some of the Caribbean Groceries (Orleans, Kool Runnings Caribbean Groceries), they are also good for dried goods and spices (in some cases unique ones too).