Cyclonic Rift is $0.10 on Magic Online but $32 in paper. For example, Sylvan Library is $0.02 on Magic Online and $45 in paper. And this includes a lot of really powerful and playable cards, especially Commander staples. While it is true that it's going to cost a lot if you're going to run out and buy an entire top-tier Modern deck with cards like Ragavan, Nimble Pilferer and evoke Elementals, the way the Magic Online economy works is that only a handful of tournament staples (especially Modern and Legacy staples) are expensive, while most of the other cards on Magic Online cost close to nothing or, in some cases, literally nothing. One popular misconception about Magic Online is that it's an extremely expensive way to play Magic.