I'm looking to invest in rental income properties but due to the fact that multi-family properties where I live are expensive, I would need to go further out to find better deals. 

How far is too far,1 hour away or 2 hours away? 

Whats a general rule of thumb when it comes to buying properties bit further out from where you live? 

Thank you!

Depends on you. One of most important things is that you know the area you are investing, can be on other coast but even numbers are not as important as knowing the neighborhoods. Many investors seem to start with area they lived in because they know the market and the true value. Things like zoning and section 8 ratios can play a factor. Just a few quick points

@Christian Pietrantonio A general rule of thumb is if you cannot find good deals in your own area, then try the areas/places you visit often (family or friends). At least this will allow to have some "boots on the ground" if you need help with something quick from a local person.