The one on the left reminds me of this. Highly recommend messaging the seller to get the back made higher. It will fit much better and need less alterations. Feel free to ask questions about this one. I had a great time working with the seller. https://smile.amazon.com/dp/B07HRMC399/ref=cm_sw_r_apa_i_2Q5LEb70T38Z9
The one on the right reminds me of some things I've seen on Nordstrom's and Lulu's and this from Amazon: https://smile.amazon.com/dp/B07VWJ9JXC/ref=cm_sw_r_apa_i_tT5LEb1CD361Q
Also look for Amazon sellers with reviews, rather than specific dresses with reviews. A lot of sellers are well reviewed, but they come out with new styles that no one has bought yet.
Other sites to check are 1861.ca and asos.
I got this dress from Amazon that I plan to wear for my rehearsal! It’s pretty good quality and just as pretty in person. I felt it ran a bit big and exchanged it for a size smaller, but I had an overall good experience!
My actual wedding dress is from lulus, which I got for $130. Lulus, azazie, and boutique 1861 had good options within that price range IMO