Set initial fee to min_fee, use min_fee in change calc

src/wallet/wallet.cpp

@@ -2841,7 +2841,7 @@ bool CWallet::CreateTransaction(interfaces::Chain::Lock& locked_chain, const std
             // Get the fee rate to use effective values in coin selection
             CFeeRate nFeeRateNeeded = GetMinimumFeeRate(*this, coin_control, &feeCalc);
 
-            nFeeRet = 0;
+            nFeeRet = min_fee;
             bool pick_new_inputs = true;
             CAmount nValueIn = 0;
 
@@ -3017,7 +3017,7 @@ bool CWallet::CreateTransaction(interfaces::Chain::Lock& locked_chain, const std
                     // change output. Only try this once.
                     if (nChangePosInOut == -1 && nSubtractFeeFromAmount == 0 && pick_new_inputs) {
                         unsigned int tx_size_with_change = nBytes + coin_selection_params.change_output_size + 2; // Add 2 as a buffer in case increasing # of outputs changes compact size
-                        CAmount fee_needed_with_change = GetMinimumFee(*this, tx_size_with_change, coin_control, nullptr);
+                        CAmount fee_needed_with_change = std::max(min_fee, GetMinimumFee(*this, tx_size_with_change, coin_control, nullptr));
                         CAmount minimum_value_for_change = GetDustThreshold(change_prototype_txout, discard_rate);
                         if (nFeeRet >= fee_needed_with_change + minimum_value_for_change) {
                             pick_new_inputs = false;