Hello, TCL22.

I'd like to help you out but I need more details from you. 

This may not matter a lot but let's check to see if this is caused by the decimal separator format (comma in our case). 

Have you tried entering an amount less than a dollar for other items and entries? Did you use a different format for the decimal separator? 

Also, are you editing an existing item? If so, can you try creating a new one with the same information? Lastly, have you also tried closing and reopening QuickBooks, then re-entering the cost? 

Knowing these would help me better understand the root cause of the error message. 

Looking forward to your reply.