Is a frame with this dent dangerous to ride?

In my opinion that’s just cometic.

Pretty common place to see a minor dent in an alu. frame, often from it been knocked when lent / secured against something.

As long as everything is still straight and it’s smooth with no creases it should be perfectly fine.

The only caution I’d have is buying it online without being able to inspect it up close first, and/or having no right to return.

Nah, my cousin Darrell says you can just squirt some expanding foam in there and she’ll pop right out.

When buying this used frame vs a new frame, do you save enough money to get dental implants? The dent doesn’t look too bad. If I owned the bike already and knew how it happened I might be cool with it. But, I wouldn’t buy it.