Most landlords want proof that your income (disability, etc) is 3x the rent. So if you're looking at an $800 apt, they want you to prove $2400 of monthly income. If you don't have a job, they take proof of income such as taxes or bank statements for the last few months or a couple years. If you're on permanent disability, the landlord may allow you to rent with only 2x the rent ($1600 for an $800 apt).
If you have a housing (section 8 or such) voucher, that may also limit your options. (Altho, you're in Cali, so landlords may have to take vouchers. In my state, many landlords won't accept them besides very large apt complexes. Too many extra rules & too difficult to evict bad tenants.)