I would not recommend a soprano for a beginner, not a good choice. If I were you I’d stick with the alto for the time being. Saxquest has some student model altos for a very good price and in the range you mentioned, and it’s the best place I can think of to purchase one. I’d steer clear of most of the online dealers in used horns, I’ve had some pretty bad experiences with some of them. I seem to have a penchant for learning the hard way. The problem with sopranos is the intonation factor because of their small size. Any inconsistencies with an immature embouchure will be magnified. Tenors and altos are more forgiving in that aspect which makes them a better choice for beginners. The horns that I bought from a few online dealers were touted as being ready to play but when I took them to my tech they were riddled with leaks in a most inexcusable manner so you end up spending more than you bargained for. Stick with Saxquest, they’re the good guys.

https://www.saxquest.com/index.php/store/category/student-saxes-C26