i've replaced keyboards or keys on a few laptops before. if replacing/cleaning the key doesn't work then you probably need to replace the keyboard. there's a ton of self help videos on youtube on how to do it. alot of cities have "recycle" electronic stores where people can donate computers and laptops, custom or not, you can probably find what you need at one of those stores and fix it yourself or have one of their techs do it (it's 40 bucks an hour here with an hour minimum)
the key should be a few quarters and a keyboard should be a few dollars