I'm blatantly copying this idea from a suggestion by Wes Osborn in the Polaris Idea Exchange (https://ideas.iii.com/forums/951742-ils-polaris/suggestions/46833076).

While creating item records, generally while following prompts in an item template, it is easy for staff to scan a value such as a barcode or ISBN into the price field by mistake, resulting in items that can incur bills in the billions of dollars if the issues are not caught. Additionally, it's easy to miss entering a decimal point and still wind up with charges exponentially higher than intended.

This could be mitigated by setting a maximum allow value for the field. Wes suggests in his idea having a default max value of $9,999...which I like so long as there is also an ability for local admins to set a different value for that if they wished.