While there are no guarantees in gambling, the 'build-up method' described in the Cowboy Slot Channel video suggests it's possible to start with $100 and potentially work up to a hand pay jackpot. The key is to start with low denomination machines, like a 25-cent slot, and aim to double your money. If successful, you gradually move up to higher denomination machines, setting aside your initial investment and some profits as you go. It's important to stick to low volatile machines and be disciplined with your budget. Remember, gambling is a risk, and there's always a chance of losing.