No need for a plugin to put the Facebook Like button on your posts. Paste this where you want the button in your single.php or post.php depending on the theme you’re using:

There are several settings, so if you want yours to look different than mine, generate the code here.
Then, put in

where the URL is in the code, as I’ve done above.
(I’ve had to include carriage returns in the code above to get it to fit in the space. You might need to take them out when you paste in the code.)