It's a bit slow at the beginning. Assuming you have no chips, just select single line at a bet of 5 and start playing.
Since the odds of winning anything at the start isn't that high, it might feel like it's gonna take a while, but you will win something given enough determination.
When you do, you'll very likely get enough chips to immediately swap over to 5 lines so do that, but don't increase the bet yet.
Now just spam the roll button. With the increased odds of a win, you're more likely to win something, and if you're lucky, you'll win again before you run out of chips.
It's still a bit shaky at first, but win a few times and you'll be rolling in chips.
When the amount of chips you're winning seems insignificant compared to the amount you have, increase your bet by a bit. Just be careful and know when to back down your bid.
(One thing to note, you do not need one quadrillion chips to get everything in the shop. I got that many because I felt like it.)