At 20% down (on a seller carry for example) the HELOC would cost $150+/- per month (but could and is likely variable).

Usually the higher the rent, the better the property and location.I know there are a lot of variables that come into play when choosing investments. 

Most lenders will do HELOCS up to around 90% of the appraised value, or higher, and it will take a "second position" to your existing mortgage, meaning that if your home is foreclosed on for whatever reason, the proceeds will go to pay off the lender holding your mortgage first and if there's any left over then they'll go to pay back the HELOC lender.When evaluating HELOC options vs each other and other possible loan products, definitely scrutinize the terms because most will have variable interest rates after a certain "introductory" locked-in period. 

I do know HELOCs are higher than the market mortgage rates and are variable which is fine by me.Tam

@Paul Wakefield There's tons of variables to consider.

Typically, HELOCS are variable interest rate loans however you only pay interest on what you utilize (typically).

So my basic is 4.25% Vacancy, 5 or 10% OpEx depending on condition, and a variable amount on CapEx depending on rent roll and age of home components. 10%  can be a safe number. 

Your first deal should come from your pocket and should utilize the best low-down loan option you have available to you.You're not likely to get pre-approved on a part-time job with variable hours to the extent you'll be allowed to buy a duplex, however, it may be possible to get a townhome or a condo to start the equity ball rolling provided you've got a good stable job and 2 years of consistent employment.  

I recommend you do this each year to adjust for utility increases and other variables.

That is often how it is heard.There is a lot more to say about this topic, a lot of variables and things to consider or talk about.