Tinto de Verano or Spanish Summer Wine.
I do love good homemade Sangria, but honestly speaking in summer you will find me (and the most other locals) drinking Tinto de Verano a lot more often. Tinto de Verano (literally translated as Summer Red wine) maybe doesn’t sound as fancy as Sangria: just half wine + half soda, but it is easier, faster, fewer ingredients, and arguably more delicious!
I have a Sangria video recipe as well, leaving it here under the video description.
So, for Tinto de Verano you will need just 2 ingredients: Red Wine and Soda (can be lemon-flavored or not, as you want ).
Being a Summer drink, Tinto de verano always goes over ice, often with some slices of lemon or orange.
As for wine - you will need just a simple table red wine.
As for soda - it is better to pick up some mild-flavored, low-sugar one. In Spain we typically use La Casera, with is the best-known brand. But as you don't have it, you can use instead Sprite or 7up or lemon Fanta. If it turns out too sweet just add some unsweetened carbonated water. The sweetness level is entirely up to you.
Just like with Sangria, there is no single recipe for Tinto de Verano. The common proportion is 50 / 50 but depends on your taste. Even in bars, if you ask, they will bring you separately wine and soda so that you can mix in the proportion you like in case you want more wine or more soda.