I have slightly wider than average feet. I choose shoes carefully because if they are too narrow not only is it uncomfortable generally but I too have bunions (amazing how many people think they are funny!).
I never wear plastic shoes, never buy unless I have walked around the shop a couple of times in them, and funnily enough the only time I had my feet measured for shoes I relied too much on the measurement and not comfort and threw them because they pinched!
Try Clarks, they will measure. But I just take my time, choose shoes that make my feet look smaller, less buniony, and feel like they 'are the ones'. Careful shopping means my bunions, a family trait, have become no worse over the years and very rarely cause me pain.