You can find many threads on here for the Millennium One, the Chessnut Air, and the Square Off Pro, all of which are available and under $300. There's also the older DGT Smartboard. I myself was pondering that question, but I've ruled out the MIllennium because of its cheap build-quality, am curerently leaning to the Square Off Pro (size, portability). All boards have their strengths and weaknesses.
Just look at those threads, there's tons of information.
I was looking to buy an electronic chess board and under a budget as well, but I'm having trouble deciphering what are scams and what are legitimate products. I'm also noticing that a lot of electronic chess boards have a lot of features I don't need, like companion apps, self-moving mechanics, or even the capability to play online, which isn't super important for my use case. All I need is a board that can live display moves as they happen, onto a chess.com board.
Any and all recommendations are welcome, I would greatly appreciate your advice.