Seat or complete toilet?
At this budget you can have a very good bidet seat on your existing toilet, or a basic complete toilet without one. If your current toilet is sound, the seat is usually the better value.
If you are replacing the toilet anyway, a WASHLET+ set at the top of this range gives you both with the cord and water line hidden.
What changes in this range
You get the features that make a bidet feel like a proper fixture rather than an add-on: a heated seat, adjustable warm water, a remote, and on many models a warm air dryer.
TOTO's WASHLET S2 and S5 sit here, as do most of the well-specified third-party seats.
Warm water still matters
Some seats at this level still heat water in a tank rather than on demand. If more than one person uses the bathroom in a row, look for instant warm water — it is the single feature most worth paying up for.