This will really help you to see how many houses are within the type and value range that you are looking for

Most investors are happy with a range of 8% - 12% cap rate. 

If I approach a seller in the Los Angeles area with one of these types of deals are they going to take me seriously or just laugh since we are most likely talking about something in the 400k-500k range?

They are desirable for a wide range of tenants (students, single professionals, retirees, etc) and I'd love to add more to my portfolio.

I'm not only looking at those two cities, I'm actually open to anything that fits my $30-50k range.

The properties I am targeting are in the 25k - 60k range located in Milwaukee.

I've been shopping 6 months and this is the highest rental income I've seen for my price range (under 350K).The rents seem very low to me.

Keep in mind that this is in San Diego in the $500-600k range that I have seen this so I am not sure how your home will compare. 

What price range will you buy in?

You'll want to keep your good tenants in the property as looooong as possible - cash reserves required by lender for your purchase - you'll want to see how much they require to see the range of property you can afford - overestimating occupancy - if you have a resident move out that's likely a solid 1 1/2 months without rent (depends on market but I'm just using averages) and if you have to evict that's likely 2 months without rent