The state Danish-education system: structured classes, free for most residents.
Details
Lærdansk runs language centres across Denmark delivering the official danskuddannelse programme up to the Studieprøven, tuition-free for residents referred by their municipality, though self-supporting students and workers pay a refundable deposit per module. If you live in Denmark this should be the spine of your learning; nothing online replaces a teacher and a class of people at your level. Only relevant inside Denmark, and availability and pacing depend on your municipality.