Getting there early also means the shelves are still neat so you can actually see what you need instead of digging through a messy pile. I hit my store at 7am too and the produce section alone saves me money because nothing is picked over or bruised yet. Plus the first markdown stickers go on around that time, so I grab meat and bakery stuff cheap before anyone else even walks in. Store layout is a huge trap, they put the pricey stuff right at eye level and the deals way down low, and when it's quiet you actually have time to look.

But you are comparing apples to oranges here. A plumber has to cover truck costs, insurance, gas, tools, and the time driving to your house, so that $340 is not just for the 20 minutes of work. You got lucky if those clogs were all near the drain opening, because a real main line blockage or tree roots in the pipe will laugh at your $60 snake and you will be calling that plumber back anyway. I have seen cheap snakes just push the clog further down or kink up and break inside the pipe, which turns a $340 job into a $900 one.