How to clean Kuerig Coffee maker without expensive descaler liquid?

I clean mine using white vinegar, pour through and then pour plain water

This may help... good luck. https://www.wikihow.com/Clean-a-Keurig-with-Vinegar

My regular old coffee maker ( 12 cup) cleaner is clear/ white Vinegar. You fill it up and let it run through ( reusing the vinegar) probably twice, then fill again with clean water and run again ( maybe also twice) with clean water both times. I Don't know kuerig coffee makers at all really, but I imagine the same basic technique will work.

While the parts are " sweaty" with the vinegar- spots and goop in the drip crevices are easier to wipe away with a paper towel ( q tip perhaps). I try to scrape/ wipe the crud off the plastic grooves and I put the glass pot and plastic " basket" in the dishwasher. Sometimes the glass needs a bit more active scrubbing with hot water, dawn and sponge. But the brown" scale" will come off.

After a cleaning, the pot fills ( the hot water runs through) significantly faster and coffee tastes good.

I also try to reuse some of the hot vinegar (for cleaning). At the very least pour into toilet rather than just down the drain. A gallon of vinegar costs about $3- ( 2.99/ 1.99 on sale?) at my local grocery store.

Use white vinegar. Pour it in and run that thru the coffee maker. Follow up with a few batches of fresh water. White vinegar will clean any coffee pot. I also used to soak the water bath of my humidifier during the non-heating system. Poured it in and let it work over the summer to attack the scale.

Thank you!

White vinegar I run two cups of white vinegar through mine