@Gahrling already stated for buttons that dirt cheap you are going to get crap.
Getting good, quality arcade parts are not going to be cheap.
Having the really cheap Mainland Asia made arcade parts and the real authentic arcade parts side by side, you can really see the difference.
The differences between the two groups are like night and day, the cheap parts are going to ether feel like mush or feel gritty like someone poured sand inside, maybe they would squeaky.
And the worst part with these ultra cheap parts is the quality is going to be completely inconsistent, you can have two nearly identical knock off buttons and one will feel like mush and the other sounds like a cement mixer.
Now with actual authentic arcade parts, the action and movement is going to be silky smooth, the variation would be with the model or brand of parts used instead of every individual button.
The buttons will move smoothly, you feel and hear a satisfying click with the activation of authentic parts (with the exception of silent/silenced parts which has padding inside).
The comparison between the knock off and authentic parts are like driving a old beaten up Yugo compared to driving a well keep Royals Royce.
You really get what you paid for when you buy Arcade parts. Brand names aren’t an excuse to mark up the price but a guarantee on quality.
But if you really want to go on the cheap, go on and by those 30 buttons for 4 dollars. I see there 4 colors pictured but there no indication what colors you are going to get
Are you going to get a even near even amount of colors (30/4=7.5) or is the colors going to be a random selection. Another indicator that you are basically throwing your money away.
But it’s your money.