Suggestion:
The easiest platinum trophy I got was from God of war 2. You could get the God of war collection, it is less than $30 and you get 2 games.
I like this site it has walkthrough for trophies (some sites just show you the trophies, they don't show how to get them), maybe it can give you some ideas and it will also help you to get more trophies with the games you already have. Good luck with getting trophies!
http://www.ps3trophies.org/index.php
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I think all bronze are really easy to get. Most of them just involves killing a sub-boss or boss, getting past a certain stage, or finding a secret area.
I thought God of War 3 was really easy to get bronze trophies. Dante's Inferno is also easy. The God of War collection.
easiest one would be dragon age origins or dynasty warrior 6…..takes a while but their all easy