Pots don't have to be overly expensive. For example this rectangle is roughly 16 inches in length, it is a "production grade" pot from Japan, no signature, but it is well made, and fired high enough that it is reasonably frost and freeze proof. It was only $75. This is quite reasonable for a large, winter proof pot that can be used for conifers. Kilns large enough to fire 16 inch and larger pots are uncommon, hence larger pots tend to be more expensive.
This second example is a very well made signed piece by the USA potter, Lynn August. It is a 6 inch round, frost resistant, burnished finish, not glazed. I picked it up at auction some years back for only $45, which is about right for a USA made pot.
Both pots are "good enough" quality that they certainly can be used in local shows. The large rectangle for a conifer might be switched out if the tree in it was accepted for the National Show in Rochester NY, you would want a higher quality pot if the tree got accepted to that show. The Lynn August pot is high enough quality that her pots in this style have already appeared at the National Show in Rochester.
So the point is, some $45 pots are Exhibition quality. You don't have to spend huge money to have nice pots. Shop around, you can find very useful pots at modest prices.