I guess I'll start with a little background info. I recently got a Canon Rebel T3 and it's my first DSLR. I currently have the basic 18-55mm f/3.5-5.6 lens that came with the camera kit and the Canon 55-250mm f/4.0-5.6 ISII. I currently shoot still life, nature, macro, landscapes, and the night sky, but I'd like to get more into portraits. I live in the country, so there's not a whole lot of opportunities to take shots of people, but the holidays are coming up and I'll have a lot of opportunities for portraits of family members then. Most of the year though, I'll probably stick to nature photography. For my next lens purchase, I want to get something that is relatively cheap, can give me a more options to work with, and that will be the most useful. I don't want to buy a lens and then find out that I rarely use it, or end up just sticking with my current lenses most of the time.

I'm thinking about getting the Canon 50mm f/1.8 since it's only about $100 and that f/1.8 sounds really nice. I've also heard a lot of people say great things about it, but I'm not sure if that's just because everyone has it and uses it a lot because it's really cheap and available. I think it would be a great lens for portraits, but not sure how well it would be for nature photos since I mostly do that. On the other hand, I'd also like to get a nice wide angle lens for more landscapes, but I'd have to save up longer for one of those since they don't come cheap. I'm able to go 18mm f/3.5, but I'd like to do better if I could. I'm actually not sure what my best option would be for a wide angle, so any suggestion on a good one for a T3 would be appreciated. I really love night photography, and taking shots of the Milky Way, so a small f stop like f/2.8 on a wide angle lens would be really nice for that.

So my question is, should I spend the money now and get a 50mm lens, or put that money to saving up for a nice wide angle lens and if so, which one? Even if you think I should go with the 50mm first, I'd still like some recommendations for a wide angle lens if you have any.

(EDIT) Thanks for the all the feedback. Looks like I'll be getting the 50mm and then trying to save up for a Tokina 11-16 f2.8.