@James Colon,
The MLS is a useful resource, and there are a ton of properties listed there. In my personal investing, I've found that my best opportunities for creative financing come when I'm able to speak directly with the seller. It can be challenging to speak to the seller without giving the offer through an agent. And most agents are simply terrible at understanding or discussing non-traditional purchase options. A really good agent can be an amazing resource.
I've found great leads with several non-MLS sources:
1. CRAIGSLIST (search key terms such as "must sell" "owner financing" "needs TLC" "Make an offer" "Owner retiring") These are all key phrases of a motivated seller you may be able to bargain with.
2. Bandit Signs. BRIGHT YELLOW "WE BUY HOUSES". I post these high up on telephone polls. Chances are good your local codes dept won't like these signs very much, and there is a risk they could fine you. I have a trac phone I use for these signs to limit risk with codes. The risk has paid off well for me, because I've purchased 2 rehab houses from calls I've gotten on the signs.
3. BUSINESS CARDS. Same exact color and wording as my bandit signs, and I hand these out anytime a discussion about real estate comes up. I also post these up at any diner or hardware store with a community bulletin board.
4, NETWORKING and word of mouth. Talk to everyone about what you're looking for. You meet an attorney, ask if they ever handle real estate closings, or estate sales. Then give them a business card. This strategy is how I found the 25 unit mobile home park mentioned above.
Keep in mind, these are only 4 strategies for finding non-mls leads that I've used. There are probably several dozen more methods that other BP users have posted about in other forums. Good luck, and please connect if you'd like to talk further!
-Chris