Unless your game looks really good people will probably not even notice it on the workshop. I would not pay the greenlight fee without getting some feedback first though. I'd post a demo to the workshop and see what people think about the game first.

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Greenlight is hard to get past without a lot of people already knowing about the game beforehand.

Workshop is ... well not bad but if you want a lot of feedback and start growing fanbase i suggest upload your game to gamejolt. If your game is at least half decent you ll get a lot and lot of feedback and can serve great as base of your operations for greenlight. In addition a lot of "begining" youtubers pick the games there and even their videos dont bring much of extra publicity its worth thousand of comments,suggestions & bug reports to actualy see unknown person playing your game.

Put it on GameJolt. Wider audience that doesn't need GameMaker installed.

As for GreenLight. A lot of things make it through the process if you give it enough time.

You can put up as many games as you want on greenlight after paying that fee.