Even systems that work across all market conditions lose trades. They aren't the Mythical 'Holy Grail', those simply do not exist, The closest you will get to a pure win only system, is by using latency arbitrage. And while that would work, your broker will quickly catch on, and they'll freeze your account. There are systems that do exist that will make profits across all market conditions. But, as I've said you simply won't find them being sold for $99,95 or whatever. Why WOULD they sell them? They'd have no need for anyone to give them money, they would be extremely wealthy, or at least well off enough to never need to sell it.
If it looks too good to be true, it's probably a scam! Let the buyer beware.