I saw a "just fine" no-name keyboard on sale in a retail store for less than $10.
OK, so it wasn't the greatest keyboard on the shelf, but I tapped away on one, and there was absolutely nothing wrong with the action or functionality.
A can of compressed air to blow the crap out of your old keyboard costs more than $10!!!!!
If you've dumped food or sugary/creamy coffee or chemicals on your old board... get a new one.
I guess it all depends on how fancy your keyboard is. I have two computers... one with a really fancy board with more extra buttons and keys than I know what to do with. I NEVER use any of the "quick keys." So a plain keyboard is just fine with me.

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