Try somewhere like Blue Nile [1]. The price of natural diamonds increases exponential once you go over 1ct and the size becomes rarer.

Here's a quick comparison on just size, clarity and the visibility of inclusions.

A 1ct very good quality stone, E-F, VVS2 or better, no fluorescence - you're looking at a 88% reduction in cost ($700 vs $6,000).

Jump to 2ct and it's $2,300 vs $32,000.

At 3ct, the lab grown is still only $4,200 where the natural at that size starts at $82,000.

[1] https://www.bluenile.com/diamonds

And in China and India they're roughly 3x cheaper than that, i.e. a 3ct lab-grown stone is somewhere under $1500. (I posted a link to one absolutely typical example in a previous comment.)

It's amusing that the price of gold has skyrocketed just as the price of diamonds has nosedived. Some old rings, which were valued for the small diamonds they carried, are now more valuable for their weight in gold.