Where to find a nice 1 carat center stone engagement rings for $1000?

I’m looking for a heart, pear, princess, or marquise shaped diamond engagement ring with a 1 carat center stone for $1000-1500. I’m looking for mainly solitaire but even bridal sets will be OK

For that price you will get a very bad quality diamond which I’m sure your lady would not want. Bad quality as in, it does not sparle, is milky and yellow. She will know you are cheap even if the diamond is large.

Having said that as soon as you hit the 1 carat mark prices skyrocket! Maybe go for a .75 carat diamond. It will still be difficult to find one in this price range though.
Try secondhand and pawn shops, ebay. Maybe even buy a loose diamond and have it set.