Memrise can be very useful. However, I have not paid the full subscription to see the full potential. One feature I do like is being able to take your mobile device open the camera within the app and it automatically scans the area or object and immediately gives you the item in the target language and their L1.
Duolingo is a great start to get student familiar with short common phrases such as articles, nouns, and some foods. It is free and is very beneficial. This can be used as extra study time or when students are done early in class waiting for other students to get their assignments finished.
Duolingo Podcast is another great avenue for high achieving students.
Flipgrid is a valuable tool and very interactive. This can be used to get students talking and having Spanish conversations with one another. They can respond to classmates within seconds, collect data and track participation by responding and replying to other classmates.