This was in the paper yesterday, sayings that people often quote and get wrong. These may only translate in the UK, but who knows, other countries may use them as well.
"Damp Squid"
Wrong! it's "Damp
Squib"
"On tender hooks"
Wrong! it's "On tenter hooks"
"One foul swoop"
Wrong! It's "One fell swoop"
"Adverse to"
Wrong! It's "averse to"
"Find a penny pick it up"
Wrong! It's "Find a pin pick it up"
There are more but just a few I picked out.