You can save a lot of money if you’re buying a new TV on Black Friday, but there are a few things you need to know about first.

I was just shopping for a new TV. I don’t really need a new one, but the prices are so low that I thought I could replace my aging 1080p TV with a new 4K one of the same size, while only spending a few hundred dollars.

Best Buy, for example, has several 4K TVs that are priced between $350 and $700, which is really attractive considering you’re getting a sharper resolution on a big screen. But know this before you buy those TVs.

Often, the TVs that go on sale during Black Friday have very limited feature sets. Instead of getting three or four HDMI ports, you might need to settle for one or two. These are the ports that connect to your cable box, your gaming system, your Apple TV, Roku and other products. The more you have the better, otherwise you’ll need to add an HDMI extender, which doesn’t always work well, or you’ll be back and forth unplugging cables from your TV.

HDR sounds like a just buzz word right now, but it’s more than that. You want this feature on your new TV, especially if you’re going to be keeping it for the next several years. HDR is otherwise known as high-dynamic range, and it allows your TV shows and movies to look as intended by the studio that produced them. You’ll get more light in darker scenes, meaning it’s easier to see the content. Most of the really affordable Black Friday 4K TVs I’ve seen don’t have any sort of HDR support, and the ones that do cost closer to $1,000.

Some of the more affordable 4K TVs available for sale during Black Friday only have a 60hz refresh rate. You should be shopping for TVs with 120hz or, better yet, 240hz. The faster refresh rate means you’ll be able to view motion, like football or intense scenes in movies, without any sort of ghosting effect. It’ll just look smoother, and you want the best quality possible.

Remember, and this holds true especially during Black Friday, you get what you pay for. If you think a deal is too good to be true: A huge 4K TV for $350, for example, it probably is. You’re going to get fewer HDMI ports, a TV that doesn’t support the latest HDR technology, and probably a low refresh rate. Keep in mind that some of the $1,000-range TVs are still on sale and include some of these must-have features, so consider spending a bit more and getting something that’ll really last you.