Side mirror replacement is cheap if you do it yourself and much easier than you might have imagined.
Step 1 - Remove Old Mirror
To remove the old mirror, pick out the pieces as best you can. Use a putty knife to scrape the rest away, and also to scrape off the glue that held the old mirror in place. Don’t worry if you don’t remove absolutely all of it.
Step 2 - Silicone
Apply several large daps of silicone to the side mirror backing plate. Be sure to use a silicone that will dry hard, not one that remains soft. This is vital for the side mirror replacement to remain in place on the backing.
Step 3 - Attaching
Very carefully position the mirror on the backing plate and press firmly in place so that it’s held by the silicone. You’ll need to hold it in that position for several hours, until the silicone is completely dry. The best way to do this is to wrap masking tape around the mirror. This will hold the glass firm. Leave it overnight to dry fully. The next morning, remove the masking tape, clean the mirror and adjust the side mirror replacement before you drive.