From a basic wide brimmed felt hat you can change its look into many other styles.
The photos below are all the same £5 felt hats from Primark, all created with quick stitch, you can cut and decorate to make many more better looks.
Below the basic black felt hat as you buy it.
Below a Bicorn
Below a Tricorn
Below almost a Quadricorn, it needed a wider brim really, but 4 points were almost achieved.
Below a Yokel Hat
PS these were all purchased for £1 at the end of the season by my friend Dave who the master of spotting a bargain.