Miraculously in 2020 there still hasn't been a Splunk Answer that details an elegant way to convert from float to currency.
Is this the best possible solution, or are there more elegant ways to do this? Careful of negative numbers.
eval budget_amount="$".tostring(budget_amount,"commas") | rex mode=sed field=budget_amount "s/\$$-/-$$/g"
How about:
|eval budget_amount=if(budget_amount>=0,"$".tostring(budget_amount,"commas"), "-$".tostring(abs(budget_amount),"commas"))