first of all, you should clean a keyboard regularly just to keep what you are describing from happening in the first place.
i would spend about 20 dollars on a keyboard. i would stay away from anything less than 15 and more than 25. less than 15 is obvious cuz the cheaper keyboards don't tend to hold up, and more than 25 you don't need all that crap. you won't use it anyway.
you can buy canned air and electrical contact cleaner. take the screws out from the underside and put them in a small jar with a lid.
clean that keyboard's keys and exterior last. take the keyboard and turn it upside down and lightly shake out the loose stuff inside-you will be amazed at what gets in there. lol, you may find anchovies or pieces of grilled cheese sandwiches or paper wedged in there..
there is sometimes a flexible rubber "mat" below all the keys on the better keyboards. take that out and spray it with electrical contact cleaner AWAY from the keyboard and let it dry. the reason you turn it upside down is to have the crap fall out instead of getting pushed further inside where you will never find it.
Whatever you do, Don't use a normal vacuum cleaner or a shop vac on any computer equipment to clean it. Regular vacs generate Static Electricity and could muck up your keyboard or other device permanently. That's why they make canned air..
I would clean that keyboard really well AND I would buy another one to keep as a spare to use when you are Cleaning the one you are using now. Keyboards go kaput just like anything else so take care of them. Having a spare also gives you more time to relax and do it right the first time cuz you won't have to have that keyboard immediately.