You need to supplement your income??? And you're looking for BETTING SYSTEMS?!?
If you've got money to blow on betting systems, then you're doing better than you think. Either that or you're naive enough to think you'll make money on betting sports. (I wanted to say "stupid enough", but I didn't want to sound TOO insulting!)
With that being said, here's your answer:
If anyone ever tells you they can make you "sure" money with a sports pick, they are fooling you.
The BEST handicappers out there MIGHT actually be able to make money betting on sports IN THE LONG RUN, but there is no such thing as a "sure thing". ANY single game that a bookmaker or any other sort of expert handicaps is at best a 75% winner. (I'm speaking about any game that might otherwise be considered 50-50 with a spread of some sort.) ***BY THE WAY - someone that could be that much of a favorite would really have to have some secret, inside information. A game like this would be a rare once-per-season or less occurance.*** Now if you knew you could win a bet 75% of the time for even money, you'd be a fool not to put SOME money down on the game. The trouble is, you can't put ALL your money or even a significant percentage of your money down, because there is ALWAYS a chance of losing.
The fact is, the best handicappers out there would be more likely to get 60% if they're lucky. If they can do that season after season, they could just continue to make reasonable sized bets and make a profit at the end of a season.
Anyone that uses the word "lock" or "sure thing" should not be trusted.