I had that happen and blew about 50lbs of dog hair out from under the keys. I've also had it happen when a key contact or spring breaks.
Most keyboards are surprisingly easy to replace on laptops. Not super cheap. If its deemed that your keyboard is broken and irreparable, look for the same model complete on ebay with a smashed screen for $100 or so, then scavenge it for parts.
Look online for instructions on removing your keyboard. Many just pop out if you pry in the right places and have a short ribbon cable connecting them underneath.
Be fearful when others are greedy, and greedy when others are fearful. Just another form of "buy low, sell high" for those who have trouble with things. This rule is not universal. Do not buy a 1973 Pinto because everyone else is afraid of it.