What makes a movie look "cheap" to you?

Godawful CGI like you get on the made-for-SYFY movies! That's my favorite!

Also, one instrumentalist doing the score. Sometimes in really low-budget 80s movies, there will be one synthesizer doing the entire score.

The exception to this is "Birdman" which had drums only, but that worked and the movie didn't come across as cheap.

Shia LaBeouf

Do you ever watch the RedLetterMedia “Best of the Worst” reviews?

Just watch Birdemic.

Shaky camera work that looks like it was shot in someone’s backyard. Teal and Orange colour grading. Bad editing with no sense of continuity or geography.

High framerate. Even high budgeted movies look cheap when filmed in 30, 48 or 60fps. They look like soap operas.

Poor editing. Most cheap movies already blown their budget just to make the production barely finished. So they would cut corners in post-production resulting in random cuts because well it's saving time to make it cheaper. They also would never do re-shoots so whatever mistakes they got they'll just skip up, resulting in stuttered flow.

Depth of field. Cheaper cameras and lenses usually provide only deeper/thicker field of focus making less blur on unfocused areas. When everything always in focus everytime it look like a home video. Also pulling manual focus on a thin depth of focus is harder, leading to more mistakes that cheap movies cannot afford.

The same can be said on Dynamic Range. Cheap cameras only provide limited dynamic range resulting in blown highlights and total black shadows with no detail.

Make ups. Movies look cheap when the make ups are too consistent. The actors look exactly the same when they are in bed just woke up from sleep, when they are in the office, when they are showering. Because maybe multiple scenes were shot the same day so they don't bother to redo all the make ups.

1/ Bad script as in the actors are saying things that don't make sense or conversations are really banal.
2/ Lack of purpose. I recently watched "The Nest" (2020) and it goes nowhere.
3/ Not sure if there is a word for this but uninspired acting. Like the actors know they are in crap/know they aren't good actors.
4/ A depressing vibe. Being Australian, our low budget films and films in general tend to be really depressing, especially over the last 20-30 years.
5/ CGI that makes it look like a computer game.

lousy soundtrack. heavy synth sounds.
hammy acting
dumb dialogue
inane plot