The 43-inch LG UK6300 is a pretty great 4K TV for under $400, with good picture quality, convenient smart TV features and decent sound.
LG UJ6300 Review (43UJ6300, 49UJ6300, 55UJ6300, 65UJ6300)
LG UK6300 TV Review - RTINGS.com
43” UK6300 LG SMART UHD TV - 43UK6300BUB
LG 43 Class 4K (2160P) Ultra HD Smart LED HDR TV 43UK6300PUE
Best Buy: LG 43 Class LED UK6300 Series 2160p Smart 4K UHD TV with HDR 43UK6300
43” UK6300 LG SMART UHD TV - 43UK6300BUB
Best Buy: LG 43 Class LED UJ6300 Series 2160p Smart 4K UHD TV with HDR 43UJ6300
LG SK8000 Review (49SK8000, 55SK8000, 65SK8000)
Customer Reviews: LG 43 Class LED UK6300 Series 2160p Smart 4K UHD TV with HDR 43UK6300 - Best Buy
43” UK6300 LG SMART UHD TV - 43UK6300BUB