CASE WHEN Expression

I'm pretty new to SQL and I'm trying to write a query as follows:

SELECT
    sp1.Doc_Date,
    CASE 
        WHEN sp1.Doc_Date BETWEEN '2022-01-01' AND '2022-01-31' 
            THEN '$52,719' . . . 

The problem is I want to cast the $52,719 as a number vice a character but I'm having an issue with it running correctly.

Any help would be greatly appreciated.

Thank you!