Some idioms are confused in the speaking; others just in the spelling. The following idioms are usually pronounced correctly, but they are often misspelled in writing.

1. waiting with bated breath
The word bated in this expression is often misspelled “baited.” For example, “We’re waiting with baited breath to hear if Rosie O’Donnell is officially coming back to daytime screens.”

The word bated is from a shortening of the verb abate. “To bate” means “to reduce, to lessen in intensity.” The expression “bated breath” is the only survival of the word in modern English. Read more here.

2. lo and behold
People use this to mean something like “and then see what happened.” The idiom is frequently misspelled as “low and behold.” Lo is an old form of “look.” Read more here.

3. pore over
Not to be confused with the noun pore (an opening in the skin), the verb pore means, “to study or examine carefully.” In expressions like “pore over a book” and “pore over my taxes,” the word is often misspelled as pour (to transfer liquid). Read more here.

4. toe the line
This expression derives from the practice of lining up with one’s toe touching a line that has been drawn on the ground. Competitors line up to begin a race or some other competition. When everyone “toes the line” in this way, conformity has been achieved. In modern use, the expression occurs almost always in a political context with the meaning of “to conform to a political party’s platform.” It is often miswritten as “tow the line.” Read more here.

5. pique one’s interest/curiosity
The French borrowing pique means “to stimulate.” The word is sometimes misspelled as peek and peak.
Courtesy: Daily Writing Tips

On point tho.