You don't need a protection/UV filter... it serves no real purpose and just gets between quality optics and taking sharp shots of your subject. For one, your DSLR has UV filtration built in. Another thing, how much "protection" do you think a thin piece of glass can provide? Over the years I've seen more lenses ruined by broken filters, than I've seen that could be definitively said to have been "saved" by a filter. Finally, a good quality 52mm UV filter... a multi-coated one that will minimize it's effect on images... will cost you about half the price of that lens.
Yes, I have protection filters for my lenses (most are B+W 010 MRC)... They are not left on lenses and are stored in my camrea bag until actually needed, such as out shooting in a sand storm.
It's an old fallacy that "pros" used UV filters to protect their lenses. In fact, back in the days of film we used them a lot because many types of film were overly sensitive to UV light and would get a color cast without the filter. Filter manufactuers and sales people in camera stores have been happy to keep the myth of a "protection" filter alive, knowing that people were easily sold on buying them for their gear....
I'd suggest get a lens hood instead, but the front element of the 50/1.8 is pretty well recessed so one is hardly needed. Plus, unlike any other Canon lens I can think of, the 50/1.8 doesn't have a bayonet mount for a hood built in, so to use one you also have to buy an adapter to be able to use the OEM design hood. So, just get the lens and use the provided lens cap to protect it when you aren't shooting.
The 50/1.8 is the most inexpensive lens Canon makes. It's capable of making pretty nice images - certainly better shots than its price might imply - and is a good focal length for portraiture (on a crop camera like yours), among other things. As mentioned, it's cheap, lightly made and known to have slower, less accurate, more erratic and noisier auto focus. It doesn't have a focus scale or even a very usable manual focus ring. That's probably good because it's not USM, so also not FTM... you must turn off AF at the switch before manually focusing it, if you don't and override AF manully you will break the AF system. The lens is probably fine for occasional use, with some harder use has been known to simply break in half.
Still, for the money, it's hard to beat. The better made EF 50/1.4 with subtly better image quality and substantially better AF performance costs about 3X as much and really should be used with the lens hood, which is a bit of additonal cost.
