Arbitrage, Matched betting, Surebetting (maybe it's just an arbitrage with a different name) etc..
Those are all safe betts, meaning that you risk nothing (on the bet, difference in the odds is always in the plus), but you can get limited..
Possible solutions are multiple accounts,aybe a bot to handle it and just scaling to more and more accounts.. Family and friends can give you their id-s, use proxy and the bot, so in practice, it shouldn't be that difficult to scale it, but you need a team (developer, experience arbitrage better etc).. As it's compounding, 1% isn't that bad as time goes by..
I'm not experienced, I just read here and there about this.. It's great, but it's out of my reach at the moment cause my budget isn't that good..
My biggest problem is that I find out about good stuff when it's too hard for new guy to hoop on board.. It's so frustrating.. There are a lots of guys doing this, but they made it big when it was in the early stage, so protection was weak..
Damn.. Sorry for bringing it up again, but if there are new ideas, I'm here to listen, and so are most of participants I guess xD
As for the fixed matches, if you have money, you're in.. Go to your nearest stadium and drink coffee in their restaurant every day.. Meet people and make deals.. But be aware that it's illegal, and that knowing about the crime and not reporting it is also a crime.. So yeah, when it's their time to go down, guess who goes with them..
Also, the player can score a goal when you don't need it and you lose all.. It's gambling, just you have better edge..
The methods from the beginning are pure math, so you don't lose because of the game.. You beat the sistem, it's just really hard atm, I guess..