Why do designers undersell themselves?

So I was bidding on this job to design a logo and I started at $300. The very next bid by another designer was $50!! I couldn't believe it. There's no way I would go lower than that. That's not even the bid that won. I think $30 was the winning bid.

I wish I could have seen the final logo. I'm hoping it looked like a $30 logo! You would have to design 2-3 logos a day to make a decent profit which would definitely hinder the quality.

The problem is that most clients always go for the cheapest solution.

I feel this is one of the worst things a designer can do is undersell their work (unless it really is worth $30). Any thoughts on getting around this?

I think some designers are so desperate for their work to be liked and used. They will settle for a low price to have their work published.

I don't know about this stuff much, I'm not a designer, I just love design and I do it because I like it and I can get paid for it... so basically I don't really care how much is it, it's still more than nothing and I'd go even for the $30... It's really not much but still... as I said... I mean, why not? I do what I like and I'll even get money for it.
But if it was my main job or the only one, I would really ask for more money, this is ridiculous...