$15k should be ok for a triplex but there could be other variables such as pitch or how many layers they need to strip that determines price.  

So beware of those gurus selling you the "it's so easy, look at all the money listed" sales pitches.

Do a TON of reading. pitch pitch pitch. tenants, lenders, sellers, agents, everyoneand in terms of qualifying rental income. call around I usually call 20-30 banks/lenders per property before one bites. they will usually take 75% of gross income to offset your DITI if you are under 2 years

It needs to be convenient and have minimal distractions.  

My experience has been :-The first 90 days on the market they will only except full price offers -Price reductions are very minimal and usually under 5%-They will not pay any closing costs or pay for a survey

The sequencing of this concept must be done correctly and their are tax issues too that must be considered  to ensure that UBTI/UDFI is avoided or minimized.

It occurred to me it may be best to build a garage/adu or large addition in order to capitalize on my lot size and the fact that I am zoned for 2 family.I am not sure my town will allow a detached garage with apartment above, but since I am zoned 2 family I should be able to add an addition with minimal/ no variances.

We have processed a lot of tenants with our system with a minimal amount of time expended on the administration end of things. 

A/C, Furnace, landscaping, stove just to name a few... its really minimal.

I have been to a few of these now and the price you pay for networking is a massive sales pitch for training classes, etc..