|Hi TD, you have not advised the Toshiba model (laptop desktop?) which may have helped.|
Expanding on Phil's comments, here in the UK, one can buy compatible keyboards for a fraction of the price for one from the manufacturer.
Also generally one can find online videos and/or step by step instuctions on how to change a kb for a particular make/model.
Before changing the kb, I would try blowing out any muck from under ALL the keys. Hold the kb upside down and blow out with a hairdryer set to cold and maximum blast, or purchase a can of compressed air from one of the cheapo shops. Use a long thin paintbrush to assist.
Please advise back on progress.
As a matter of interest, where are you located? I am in Hammersmith, West London.
Good Luck - Keep us posted.