Back in the 90s when I first started.
- bought a Simmons scope ($80) and spotter ($60) from Sports Authority. Scope didn't track well and zero was questionable. Wasted boxes of ammo. Glass had a yellow tint. Spotter was OK but it also had a short eye relief and some tint to the color. Wasted $140 not including ammo and fruitless trips to the range.
- Started highpower shooting in early 2000. Bought a cheap DPMS upper. Sights didn't track. Went to a match in AZ and found out the hard way. Travel expenses, ammo, time prepping and very shitty scores.
Yes, you can experience this path training with cheap shitty equipment. You won't get good feedback on what you need to improve.
Kowas, Leicas NF, some Leupolds, some Vortexs, March, Trijicon optics aren't cheap but what you get is reliability. As you get older time is more valuable. If you want valuable training you'll train with equipment that you can rely on.