The “Wahoo Kickr Smart Bike” you’re referencing is an actual full trainer bike that’ll set you back 3.5k bucks, obviously way more than your budget. I think you’re asking about a bike to use with the Wahoo Kickr trainer, specifically the top of the line direct drive trainer.
If this is the case, then just about any good road bike will work. You should be able to purchase a good used bike to use on it. I’ve built up several trainer specific bikes that only have a frame, drivetrain, seat, handlebar and front wheel. Even cheaper but you need to have someone build it if you’re capable of doing it.