We used to buy kits like that, but eventually I went to an Indian supermarket, it was quiet so I asked the woman what spices I needed to make authentic curry, I came out with a big bags of things like Garam Masala, (aromatic spices mixed) Turmeric, Coriander & Cumin, she told me a teaspoonful of each but then taste the curry as it's cooking and adjust. Add coconut cream if desired (if you use half a tin you can freeze the rest).
Anyway turns out we have enough spices for the next 10 years all for about 20 quid. They don't have any use by date or any of that nonsense. Try it, you can get very good at it.