Maybe a tiny shed or something similar but no full size buildings. 

But since I don’t know what city you live in, you might need to ask yourself real quick, if the market size and activity level could sustain some ups and downs, especially since both you and your girlfriend are agents.

I find that 2-3 listings for every 10 are being listed at below market price.Besides leaving contingencies on the table - inspection, appraisal etc...

He is willing to come down on price in exchange for me handling removing the tenants myself (from $105 to $100k), and this was a solution I brought to the table, not him. 

Keep in mind that the cost of borrowing $100k more is in the neighborhood of $500/month and your neighborhoods, parking and size of the property and building change as well which changes the $$$$ you can make.

BBQ, firepits and tables out back, party lights, cornhole, horseshoes....games and books inside.

((Best)) way I can think of is have some money to invest and partner with a more experienced developer who is doing what you want to do.Come in as a Jr. type partner in the deal, and work full time at it--learning.By Jr. type partner I mean you are not calling the shots, but are in on all meetings and all aspects of the project.After a few deals maybe you want to go it on your own, or maybe just keep on partnering....A good partnership is a definite strength--but it depends on the person.I would say that is the (BEST) way to learn a particular development type.If you lack meaningful money try befriending a few developers and just talk shop as well as friendship things, and see what turns up.But to be a developer you will need to have a good sized chunk of change to risk (possibly losing) to do a deal.Good Luck!

Basically, the name of the game when you start out is to pick a market that makes sense in terms of population size & growth, job growth, demand for housing, and prices within your budget.

The bigger the ADU size, the lower the cost per square foot. 

@Jacob VosWinkel  $2,500/mo could either be a lot or not so much depending on the size of the facility and the acquisition price.