IF Statement- To Remain Blank Until An Amount Is Entered In That Row

Amount Amount Item Total Account
$ -
No Profit$ 629.50 $ - $ 629.50 No Profit$ 46.29 $ - $ 46.29 No Profit$ 2,333.01 $ 233.30 $ 2,566.31 233.3
$ -
No Profit
$ -
No Profit
$ -
No Profit
$ -
No Profit
#1 If there is an amount in column B, I want column D to reflect that amount.

#2 If there is no amount in column B, I want column D to state the words "No Profit."

#3 Already in column B is the formula =C1-A1.

I tried =IF(B1=0,"No Profit",B1) but when I copy that formula down the spreadsheet, it inserts "No Profit" into all of column D. I only want "No Profit" to exist when there is a $0 resulting from the formula mentioned in point #3. When there is a blank cell in column D, I want it to remain blank until an amount is entered in that row?