Hi, ok, I'd like to apologize for not having done an exhaustive research before correcting you.
My judgement is both based on personal opinions and results on Google.
Previously I only thought that the usage that gained the most linguistic currency would surface but perhaps failed to bargain for those that did not appear in the results, the latter I guess could be words of less popularity but still acceptable.
Second, you can note from the above that I disclaimed the fact that my interpretation of natives' views is entirely correct. I may not be a native. However, let just say that when you have studied and been immersed in a language for some time, you'll know what phrases or words, when used in a particular context or with a specific shade of meaning, will sound natural or not. This is, I think, a normal skill every language learner should acquire at some stage during the course of their study.
Furthermore, I didn't say that they would find your phrases incomprehensible. Instead, I said that without making some efforts, they could hardly grasp it at first glance.
Since you insisted, I'll review the errors:
increase the amount of learners pay
=> I interpreted this in two ways
+ You were referring to the number of learners: learner is a countable noun. Therefore, its quantifier must be a count-quantifier such as "number", not a non- count one like "amount". Second, it should be correct only if either you place behind "learners" a relative pronoun, in this case "who" or "that", or you change "pay" into a gerund, i.e paying.
+ You were implying that learners have to pay more: in this case, the error is conspicuous and doesn't require further explanation, right?
no cost university
This should only be grammatically acceptable if you place a hyphen between "no" and "cost".
instead discourage them from studying to enter the job market earlier
This is mostly based on my feeling. Since there is not a definite structure that can govern the whole phrase, I cannot judge this to be wrong from a grammatical viewpoint.
That's basically all of it, isn't it?
Finally, it's just my advice to be mindful whether one of is of official and popular use when writing, you can take it or lump it :D