When buying spirulina, make sure to purchase high-quality algae from organic sources, which are from clean and controlled waters and from certified producers. Spirulina is available to buy over the counter or online at: - drugstores - health food stores - some grocery stores - huge online shops which have drugstores, such as Amazon. Blue Spirulina is relatively costly, in comparison to the green variety. 1.76 ounces cost about 30 dollars (at least it did in 2021). Here in Germany, you will pay about 12 euros (approximately 14 dollars) for 30 grams (1.06 ounces). Having said this, you only need a small amount for your recipes, which makes it totally worth it.