I got some major legal heat when I was a teenager. i used to book high school and college kids $25-$100 bets, I would never even think about doing it again. What i did though that still makes me great money after closing up shop wasset up a website and give information about what the best and safest online sports books were. I did this back in the late 90's. I promoted it almost entirely by word of mouth and referrals. It got the the point at bars people would ask for a good bookie and people would say do you have internet? If they said yes they would say: (the website I owned.com). I was really involved in the local scene if people had a slow pay, miss grade, or even rules question or w/e they would call me up or find me in person and i would help them.
At WWTS i had 250 referrals all from warm market, had about 80-100 at at a bunch of others.
I still make money from a few of the sites like Bodog but sold the site a few years ago at a nice price to raise some quick money to get into marketing online poker. I kept all my affiliate accounts just sold the site and started new ones.
If you have a local market who gambles this is much easier way to make cash then actually set up in the business.