@Christopher Bannister
I agree with what others have said. The 1% rule is a quick rule of thumb that can quickly remove properties out of your way. For instance, if the property is worth $120K after cosmetic updates, it should rent for at least 1% of that ($1200/month).
But then that brings the questions "How do I know what it will be worth after updates?" and "How do I know what it will rent for?"
The two questions above could still take you a lot of time to answer. Here's how you can shrink that time as well.
What will it be worth?
I have access to the MLS, but this can still be done on Zillow and similar websites. I pull comps within the area that meet the following criteria.
1) Within a quarter mile (in the suburbs, I may go out further)
2) Within 20% of the square footage
3) Similar or less desirable category (i.e. single-detached, semi-detached, rowhome..)
4) Closed within the past 6 months (maybe further back if there's a lack of comps)
5) Similar or worse condition to what the subject property will be in after renovation
I'm thinking from the perspective of a bank appraiser as I pull comps. Because ultimately the goal is to buy, renovated, rent, refinance around 75% LTV, and repeat.
If your goal is to refinance all your cash out, you want to be all in at 75%. So your purchase price and rehab should be 75% or less of the ARV. For example, $52,000 purchase + $3000 closing costs + $20,000 rehab = 75% of $100K ARV.
What will it rent for?
If you do not have rent-o-meter or MLS access, here's a very quick short cut. Section 8 housing publishes what they determine to be fair market rent within each zip code and for each bedroom count. Even if you aren't planning to accept section 8 tenants, it's still a good rule of thumb for knowing which zips rent for how much without having to pay for a subscription.
Click here to go to the website. This is what you can expect...
Again, this isn't perfect. But it does allow you to quickly determine which properties are worth pursuing.