Does the 75 dollar receipt limit apply to all business expenses

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No.  This only applies to travel, entertainment, gift and transportation expenses.  

From the IRS: "If you deduct travel, entertainment, gift, or transportation expenses, you must be able to prove (substantiate) certain elements of expense. This chapter discusses the records you need to keep to prove these expenses. 

Documentary evidence. You generally must have documentary evidence, such as receipts, canceled checks, or bills, to support your expenses.

• Exception. Documentary evidence is not needed if any of the following conditions apply.
• You have meals or lodging expenses while traveling away from home for which you account to your employer under an accountable plan, and you use a per diem al- lowance method that includes meals and/or lodging. (Accountable plans and per diem allowances are discussed in chapter 6.)
• Your expense, other than lodging, is less than $75.
• You have a transportation expense for which a receipt is not readily available."

(From: IRS Publication 463)