@Stoney-B 

I'm assuming this is a sole proprietorship  Create a non-taxable service product and select your equity account under 'Income account'.  The equity account is generally "Owner's Capital" for a sole proprietorship (although yours may be called something else).  Then, add that product for $50 to your invoice.  That will increase your equity in the business by $50.  Then, when (or if) you withdraw the $50, assign your Owner's Draw equity account to the payment to yourself.  That will keep the $50 off your P&L and your equity in the business will be the same as before - assuming you pay yourself the $50.