I am a realtor now and it can be difficult to obtain MLS access without having your license. Do you have a local real estate investment club? Before I was realtor I was in such a club, and many of the members were willing to help other non-realtor members with comparables. I worked well with one realtor/investor in particular and so I funneled any friends/family referrals to her in return for her help with comparables. She also set me up to receive emails for new listings that were undervalued.
