I’m a firm believer that there are a few places in brewing where you shouldn’t try to cut costs, and sanitisation is one of them (yeast is another). Buying decent, brewing specific sanitising gear may cost a little more up front, but all you need to to is have to chuck a brew due to infection, or contamination from your cleaning regimen and your cheap option all of a sudden isn’t so cheap.
PBW/Sodium percarbonate/unscented napisan are great for soaking soiled brewing gear (Stainless and plastic), and if rinsed properly won’t leave any residue.
A quality no rinse (starsan or other) is a good option for fermenters/kegs/lines/bottles/cubes/caps (basically anything the final produce comes into contact with).
If both are used properly, then the cost per use will be at most $1-2 if you’re making large batches. Well worth the outlay If it means you’re not tossing out $60-100 worth of wort.