1. Cheap and Audiophile are words that do not go together.
2. Cheap "consumer grade", maybe?
Anywho. The idea is that "monitor" manufacturers, irrespective of price, do the best they can to make things sound "the way they are" - period. Consumer OR maybe audiophile speakers(Don't tell any of them!) are made to sound "good" - period. OK, possibly to sound "impressive"? Hard to say. Fer shure, professsional audio monitors and high-grade audiophile speakers have one thing in common - they are always expensive.
That said. Does a pair of ANY 300 dollar speakers qualify as anything other than "consumer grade" - whether labeled as monitors or otherwise? Hard to say...
When you spend whatever you spend you're looking for what? I'm looking for a "solid", well-built cabinet with the best possible speakers for the price, and a design that appears to reflect what I want to do with them. Not a penny more for a "Cherry wood" finish, no meaningless "features"! I'm looking for a professional "input"(Balanced XLR). Most of all I'm not LOOKING for anything! What I want to do is HEAR what I need to hear! No "extra" bass, etc. If it's garbage I put in, it's garbage I want out. If nothing else, the manufacturers of "monitors"(at any price) have at least made the statement that they are trying to give us what we want(Whether they do is up to our ears.). The "other" speaker manufacturers have, generally, made no such commitment. Still, if I had a few grand to spend, I might "bite" on a pair of Thiehl "audiophile" speakers? Nah, I'd likely go for the..? Hard to say...
Are ANY speakers "good" for monitoring for 300 bucks? Yeah, probably. My tiny Yamaha MS50's cost 99.95, and they do fine for what I need. They are built like tiny tanks. I hope to "upgrade(If that is the proper term for such a meager future purchase) to the Yamaha MSP5's(About 500 US). Are they "better" than the 500 dollar Polk's? I have no idea - but at least they "say" "monitor" and I'll bet they're well-built and that at least someone, somewhere in the Yamaha organization tried to give me what I need, within their(Then My) allowable budget... Gotta' trust somebody! Sometimes that's the best I can do......
TG