I went to one of these "buy rental units and rent them and get rich" deals, and the guy there explained that if you have 10 units that you pay say 800/mo on and you rent only 8 for 1000, you've broken even, but if you can't rent them all try to rent the rest out at a loss so that the net will be positive, for example rent 6 for 1000 and the other 4 for 700 to get +800/mo net instead of bleeding -3200/mo.
That is close to the dumbest real estate advice I've ever heard. First off, you know what a house rents for before you buy it. You don't set the rent based on other properties. Secondly, if you can rent 6 at $1,000, why can't you rent all 10 at $1,000? Renting houses (or apartments) above what the market rents are -never- works. The only people you will get to move into your house at higher rents are those people who don't intend to pay you in the first place.
Here are the golden rules to buying rent houses (at least in Texas) ...
1) Never pay more than $100,000 for a rent house
2) Before you buy it figure out what it will cost to fix -everything-.
3) Check the market and see what a fixed up house is worth.
4) Pay much less (purchase price + repair costs) than the market price from #3
5) When you buy the house fix it up so its nice and things won't be breaking all the time.
6) Figure out what houses rent for in the neighborhood and charge that or -less- than that (even though you house is propably nicer than the others)
7) If the rent you're getting isn't more than $100 more than what your mortgage payment is (including insurance) don't buy the house.
Finally, when you are fixing up a rental house, don't make it so nice that you'd want to live in it. Don't buy that $1,500 stainless steel fridge when a $400 white one cools just as well. No hardwoods, no granite counter tops, etc.