For the first time in about 4 years I'm flying on United without status. I have a trip coming up CLE > CUN, non-stop, and I have an upgrade option of $582 round-trip. I'm thinking that's not quite worth it for a 3.5 hour trip, but does anyone know if this offer could fluctuate leading up to the trip?

I tried searching for the answer but couldn't find anything recent about this.

Thanks!