Should I buy a gaming monitor or a regular monitor?

At this budget the distinction matters less than the specs. Look for 144Hz and 1ms response time regardless of how it is marketed.

Is a mechanical keyboard worth it for gaming?

It depends on preference more than performance. Start with a budget membrane or entry mechanical and upgrade once you know what you want.

Yes. A 27 inch 144Hz monitor, a solid keyboard, and a good mouse handle both well. That is part of why this budget range is worth it.

Guide preview

Build a budget gaming setup under $500 with the right monitor, peripherals, and audio, with no RGB tax and gear that performs at its price.