I've used this HDMI to VGA adapter with good results. VGA to RGBHV cables are pretty common and not expensive unless you need insane lengths. ...

For example, your TV likely has HDMI 1.4 connections, which max out at 3,820x2,160-pixel resolution at 30 frames per second. If you've gotten a new 4K monitor, you're limited to 30fps.

Ballpark figure for a HDMI to VGA decoder is around 200 mA at 5 volts. That's a watt. For such a small device, you're going to expect that to make it fairly warm.

HDMI is really best for connecting a PC to an HDTV. Consequently, I’d go with a DVI cable. That’ll give you a pure digital signal (VGA is analog) and a much sharper picture at higher resolutions.