How about a calculated field?
Travel cost = IFNULL(SUM([Travel Cost]),0)
That should return zero if there's no data.
I did some research and didn't see a way to substitute text for numbers other than the way you've mentioned.
Thanks for the response. I have tried the calculation which you have provided. But the issue is if the corresponding dimensions are not present then it will just take away the sheet. For example, we have data until Q2, 2018. But if the user selects Q3,2018 then the calculation will not work resulting into disappearance of the sheet.
Thanks and Regards,