This simple fieldtype makes it slightly easier to work with dollar amount entry fields, and may be easily modified for other currencies. It accepts some reasonable input formatting...

• $1,500
• 120.00
• $5

...but strips it down and stores integers for easy sorting with template tags. Note that it'll output the stored int value in templates, but that can easily be fixed with Price Format or some quick PHP.

This was created for a client project where we needed to be lenient with input but store values uniformly for entry sorting on the website.