Not everyone want to use UV filter for their Canon SX50 as protector. Some do think it can effect the photo quality. It can if the filter is a bad quality cheap one. Also you need to buy a filter adapter if you want to fix a UV filter to your Canon SX series camera.But keeping the Lens protected is important too. So the only other thing you can do is using a good lens hood for your expensive bridge camera.
Latest SX series cameras like Canon SX30, Canon SX40 or Canon SX50 doesn't come with a Canon Lens hood so you need to buy one separate. Not everyone buy it but if you prefer a Lens Hood to UV filter then you should get one which custom build for these cameras. If not then you will need a to use 58m or 67mm filter with a same size Filter adapter. That can cost you at least around $30. So this one is the cheaper solution even thought it won't give you a full protection from dust like when you use with a filter.
So here's a low cost lens hood from Amazon which can be mount of any Canon SX cameras from Canon SX10 to SX50. It's a custom build so it would fit the groove type threads these cameras have. Also it cost you only around $7 with shipping and everything. It's same as Canon LH-DC60 Lens Hood ( Here) which is recommend by Canon for their SX cameras in this series but cost you only half of Canon hoods price.