The context is that speaker (a child) is trying to find the meaning of a word and asks her friend if she can borrow a dictionary. The friend ridicules her. She brushes aside the insults, saying that "dictionary owners know complicated things" followed by the above sentence.
My previous attempt to translate this sentence was a disaster, so I'm going to try again. Please help me to understand my errors.
買ってやった is "bought for me"
verbかいがある is "There is value in doing verb"
I think って must be a short hand for と and I'm going to guess that there's an implicit おもう.
ものだ is one that always confuses me. It seems to be context dependent and since I'm struggling with the rest of the sentence I'm not in a position to figure out which one it means.
So here's my new attempt:
I think it would be worthwhile if my parents had bought me a dictionary too.
I don't like my placement of "too". I don't understand what も is doing attached to 親.
My parents also think it would be worthwhile if they bought me a dictionary.
is better. At least も is on the right place for that.