They still do core sets (every Summer, IIRC) that fulfill those basic edition sets. Lately, they've been set in external intellectual properties. Last year's was Lord of the Rings. Might sound bad, but the D&D set rekindled magic in my game group.

They had a Jumpstart product, where you could buy two half-decks and mix them together. But it looks like the last printing of that was 2022.

If you don't mind spending the time, you could just craft a starter deck on paper or find a list online, and then order the individual cards from a website. As long as you avoid the must-have cards for competitive players, it'll be cheap.