I don't even want to give them a counter offer until they've seen my disclosures. 

Made a offer and ended up execting the counter offer How did you finance this deal?

Sometimes when I’ve made ridiculously low offers or counter offers I’ve actually had a sort of informal estimate of the renovation costs needed to make the property livable or up to code or whatever to give to the listing agent either on paper or verbally so they know I’m not just trying to take advantage of the seller.

Seller counter offered at $50k and I accepted.

You're agent should be assisting you with a counter offer that includes price and terms.6.

Geez, just use a market GRM against the market rents and then you don't have to recalculate each time you get a $500 counter offer. 

I would expect a counter-offer from the seller with the $100 scratched out and changed to 1% of asking price. 

@Robert Naucke Jr,Not going to lie, I often think it's just a realtor being lazy and not wanting to do counter offers, but it's a part of the game.   

Be sure to also indicate it's Paragraph 5 of form PAA (and any other appropriate Paragraphs checked) that's being included.c) If form PAA is not included with a Buyer's Offer it MUST be included as a condition in a COUNTER OFFER (CAR form CO) by checking Paragraph 1 D on the COUNTER OFFER and noting "CAR form PAA".d) Depending on the property type and transaction, you may need to use another CAR Purchase Agreement.

Once you've established these, you can then subjectively try to figure out a counter-offer to make to them.BTW - you do have something to put into this deal if you decide to pursue it.