No he cannot.
if you buy a source for 10-15$ make some changes and sell it as it is yours than you are disrespecting the main coder and also prevent from people creating sources for sell.
it does not make any sense to me what you are saying.
Don't criticize me about things I've never written
I never wrote 'sell it as it is yours'
I never wrote 'sell it ..' but 'share with other ..'
So please don't reply on things I've never written
I would like to point out that if you or others SELL the SOURCE CODE, without specifying any clause or method of supply (for example 'not to resell'), then I can do what I think best of that code
I don't think I'm being disrespectful to the original creator of that code, nor damaging it in any way
Even if I decide to resell it
Conversely, if you want some forms of code protection, even if provided in source code, then specify it as a condition BEFORE making the sale
And if the conditions are also acceptable to the buyer then you can complete the sale
You cannot assume that the conditions that are desirable to you are also acceptable to the buyer, you must explicitly specify this
There is no valid rule by default