I don't have any reciepts from the last year. What is a percentage I can write off as expenses on Schedule C? Without receipts? I do have expenses jotted down, but no receipts.

What was the gross income from your business?
What is your business?

You must keep proper record. You can use bank statements, credit card statement... to prove your business related expenses.

Generally, receipts are NOT needed for expenses under $25, as long as they are recorded in some fashion PLUS are normal and reasonable for the business in question.