In Riga there is a few a places where you can buy your groceries. We when to Rimi, Stockmann and little shops. We think that Rimi is the cheapest place to shop. Yesterday we went to do our monthly restock and with 54€ we bought food for at least a month and a half and we even bought more than what was on our shopping list. Here is their site, if you want to take a look. Compare to Portugal the prices on average are a bit lower, but not much. There is at least two Rimis near our house, one at the Origo Center and a closer one at Galerijas Center. There are a lot of them all around the city so even if you’re not staying in this part of the city don’t worry.
About a place where you can buy cleaning products or hygienic/beauty products: Actually,here we found the prices way lower than in Portugal. It’s called Drogas, which is actually fun because Drogas in Portugal mean literally drugs. Check out some products and prices here. And just like Rimi, you can find one of these stores easily in Riga. Actually, in the same places where Rimi is they also have one of these stores. Hope this information will help you somehow.