Clutch problem pedal sinks to the floor

Pedal sinking to the floor is typically a failed master cylinder, failed slave cylinder and maybe both. A failing clutch has different symptoms (hard to shift, engine slips while in gear).

So good news because replacing both cylinder is cheaper than replacing the clutch. If you are mechanically inclined you can replace these yourself - I'd give it a medium on difficulty but you will be dealing with hydraulic fluid which can make a mess (and it will ruin your paint any place it touches).

On youtube there are dozens of videos on how to replace your master clutch cylinder and slave clutch cylinder (there is also a break master cylinder which is similar but not the same), So watch a few of them and see if you're up for it.