1099 on gross or net

This is one of those situations where it's not entirely correct or wrong either way.  It's more of a consistency situation.   It also takes communication between you and the vendor.

If you give him a F1099 for the gross amount,  will the vendor have the information to show the amounts paid by you for expenses?  Are all of the expenses deductible?     How is the vendor handling this on their books?

If you put the gross on the F1099, that is probably the "more correct" way of handling it.  But I can see problems on the vendor's side in computing their expenses.

 Also, how do you account for the expenses?   I'm assuming you deduct the expenses (credit cash debit expenses)...then when you pay the vendor do you debit vendor expense for the full amount or the net amount?  You would have to be careful that you don't double deduct the expenses.

However, if your accounting is correct and the vendor doesn't deduct the expenses paid by you on their behalf, then I don't see a problem for putting the "net" on the Form 1099 either.  Just have to make sure expenses aren't being double deducted.