Copy the value from a specific cell that changes each month to next blank cell in a column

In the attached example spreadsheet, I would like to know if it is possible to copy the value from cell E20 into cell E29 during the month of January, and then in February, again copy the value from cell E20 into cell E30, without the value in cell E29 changing.

In other words, I want to fill cells E29 thru E41 respectively with the dollar amounts that appear in cell E20 during the corresponding month. Is this possible by some type of conditional formula where cell E29 would only copy the data from cell E20 if the spreadsheet was open during January 1-31, then cell E30 would only copy the data from cell E20 if the spreadsheet was open during February 1-28 and so on? Is there another or better way to do this?

What I would really like to know is if it is possible to copy data from a specific cell that changes (like cell E20 in my example spreadsheet), and have that data entered into the last blank cell of a column, without the previously filled cells in that column all changing to whatever the last entered value is.

Thank you in advance for any and all help/suggestions.

Hello Adyteo,
Thank you for the swift response. Since I am fairly new to Excel, and have zero VBA and programming experience, I cannot say if your solution will work for me until I try it. Would you mind "cluing me in" on how to use what you have provided above? Then I'll try it and see how it works. Will I have to save the workbook with the .xlsm extension after inserting the above code into it?

Thank you.