Eating a variety of grains is very good for you, but if you stick to the high-priced items, then your wallet will feel it. If you need to cut your food bill, try swapping out expensive quinoa with more affordable rice or millet. On the subject of rice, long grain is cheaper than basmati, too.
Comparison: Tesco Whole Foods Quinoa is £2 for 300g (which is 66.7p per 100g), while Tesco Basmati Rice is £1.60 for 1kg (that's 16p per 100g), and Tesco Everyday Value Long Grain Rice is 45p for 1kg (that's 4.5p per 100g).