Land Value

I have an issue where so much of my population is now homeless because they cannot afford rent. I think the issue is to do with land value which is just driving up rent prices and resulting in the citizens not being able to afford rent. I have some questions if anyone can help:

1) Is a land value of $420 normal?

2) if I decrease the amount of mixed used buildings will that decrease the land value?

3) how much do your citizens pay for rent?