diff --git a/src/components/Notifier/index.js b/src/components/Notifier/index.js
index c4a9fd10..009afe0a 100644
--- a/src/components/Notifier/index.js
+++ b/src/components/Notifier/index.js
@@ -1,11 +1,17 @@
 // @flow
-import React, { Component } from 'react'
+import { Component } from 'react'
+import { List } from 'immutable'
 import { connect } from 'react-redux'
 import { withSnackbar } from 'notistack'
-import actions from './actions'
+import { type Notification } from '~/logic/notifications/store/models/notification'
+import actions, {type Actions } from './actions'
 import selector from './selector'
 
-class Notifier extends Component {
+type Props = Actions & {
+  notifications: List<Notification>,
+}
+
+class Notifier extends Component<Props> {
   displayed = []
 
   shouldComponentUpdate({ notifications: newSnacks = [] }) {
diff --git a/src/logic/notifications/store/reducer/notifications.js b/src/logic/notifications/store/reducer/notifications.js
index c4ae1c2b..d16e0c0c 100644
--- a/src/logic/notifications/store/reducer/notifications.js
+++ b/src/logic/notifications/store/reducer/notifications.js
@@ -29,7 +29,5 @@ export default handleActions<NotificationReducerState, *>(
       return state.delete(key)
     },
   },
-  Map({
-    notifications: Map(),
-  }),
+  Map(),
 )
diff --git a/src/logic/notifications/store/selectors/index.js b/src/logic/notifications/store/selectors/index.js
index 2ae6eb96..bf6371fa 100644
--- a/src/logic/notifications/store/selectors/index.js
+++ b/src/logic/notifications/store/selectors/index.js
@@ -5,7 +5,7 @@ import { type GlobalState } from '~/store'
 import { NOTIFICATIONS_REDUCER_ID } from '~/logic/notifications/store/reducer/notifications'
 import { type Notification } from '~/logic/notifications/store/models/notification'
 
-export const notificationsMapSelector = (
+const notificationsMapSelector = (
   state: GlobalState,
 ): Map<string, Notification> => state[NOTIFICATIONS_REDUCER_ID]
 
diff --git a/src/logic/safe/transactions/gasNew.js b/src/logic/safe/transactions/gasNew.js
index df804488..da8db6a5 100644
--- a/src/logic/safe/transactions/gasNew.js
+++ b/src/logic/safe/transactions/gasNew.js
@@ -1,16 +1,17 @@
 // @flow
 import GnosisSafeSol from '@gnosis.pm/safe-contracts/build/contracts/GnosisSafe.json'
+import { List } from 'immutable'
+import { type Confirmation } from '~/routes/safe/store/models/confirmation'
 import { getWeb3, getAccountFrom } from '~/logic/wallets/getWeb3'
 import { calculateGasOf, calculateGasPrice } from '~/logic/wallets/ethTransactions'
 import { ZERO_ADDRESS } from '~/logic/wallets/ethAddresses'
-import { type Transaction } from '~/routes/safe/store/models/transaction'
 import { CALL } from '.'
 
 export const estimateTxGasCosts = async (
   safeAddress: string,
   to: string,
   data: string,
-  tx?: Transaction,
+  confirmations?: List<Confirmation>,
 ): Promise<number> => {
   try {
     const web3 = getWeb3()
@@ -19,12 +20,12 @@ export const estimateTxGasCosts = async (
     const nonce = await safeInstance.methods.nonce().call()
     const threshold = await safeInstance.methods.getThreshold().call()
 
-    const isExecution = (tx && tx.confirmations.size) || threshold === '1'
+    const isExecution = (confirmations && confirmations.size) || threshold === '1'
 
     let txData
     if (isExecution) {
       // https://gnosis-safe.readthedocs.io/en/latest/contracts/signatures.html#pre-validated-signatures
-      const signatures = tx
+      const signatures = confirmations
         || `0x000000000000000000000000${from.replace(
           '0x',
           '',
diff --git a/src/routes/safe/components/Transactions/TxsTable/ExpandedTx/ApproveTxModal/index.jsx b/src/routes/safe/components/Transactions/TxsTable/ExpandedTx/ApproveTxModal/index.jsx
index b4e12d7d..d470fd98 100644
--- a/src/routes/safe/components/Transactions/TxsTable/ExpandedTx/ApproveTxModal/index.jsx
+++ b/src/routes/safe/components/Transactions/TxsTable/ExpandedTx/ApproveTxModal/index.jsx
@@ -1,5 +1,5 @@
 // @flow
-import React, { useState } from 'react'
+import React, { useState, useEffect } from 'react'
 import Close from '@material-ui/icons/Close'
 import IconButton from '@material-ui/core/IconButton'
 import { withStyles } from '@material-ui/core/styles'
@@ -13,6 +13,9 @@ import Row from '~/components/layout/Row'
 import Bold from '~/components/layout/Bold'
 import Block from '~/components/layout/Block'
 import Paragraph from '~/components/layout/Paragraph'
+import { getWeb3 } from '~/logic/wallets/getWeb3'
+import { estimateTxGasCosts } from '~/logic/safe/transactions/gasNew'
+import { formatAmount } from '~/logic/tokens/utils/formatAmount'
 import { TX_NOTIFICATION_TYPES } from '~/logic/safe/transactions'
 import { type Transaction } from '~/routes/safe/store/models/transaction'
 import { styles } from './style'
@@ -62,9 +65,32 @@ const ApproveTxModal = ({
   closeSnackbar,
 }: Props) => {
   const [approveAndExecute, setApproveAndExecute] = useState<boolean>(true)
+  const [gasCosts, setGasCosts] = useState<string>('< 0.001')
   const { title, description } = getModalTitleAndDescription(thresholdReached)
   const oneConfirmationLeft = tx.confirmations.size + 1 === threshold
 
+  useEffect(() => {
+    let isCurrent = true
+
+    const estimateGas = async () => {
+      const web3 = getWeb3()
+      const { fromWei, toBN } = web3.utils
+
+      const estimatedGasCosts = await estimateTxGasCosts(safeAddress, tx.recipient, tx.data, tx.confirmations)
+      const gasCostsAsEth = fromWei(toBN(estimatedGasCosts), 'ether')
+      const formattedGasCosts = formatAmount(gasCostsAsEth)
+      if (isCurrent) {
+        setGasCosts(formattedGasCosts)
+      }
+    }
+
+    estimateGas()
+
+    return () => {
+      isCurrent = false
+    }
+  }, [approveAndExecute])
+
   const handleExecuteCheckbox = () => setApproveAndExecute((prevApproveAndExecute) => !prevApproveAndExecute)
 
   const approveTx = () => {
@@ -112,6 +138,11 @@ const ApproveTxModal = ({
             </>
           )}
         </Row>
+        <Row>
+          <Paragraph>
+            {`You're about to ${approveAndExecute ? 'execute' : 'approve'} a transaction and will have to confirm it with your currently connected wallet. Make sure you have ${gasCosts} (fee price) ETH in this wallet to fund this confirmation.`}
+          </Paragraph>
+        </Row>
       </Block>
       <Row align="center" className={classes.buttonRow}>
         <Button minWidth={140} minHeight={42} onClick={onClose}>
diff --git a/src/routes/safe/store/models/safe.js b/src/routes/safe/store/models/safe.js
index 9603aa0a..2ef03995 100644
--- a/src/routes/safe/store/models/safe.js
+++ b/src/routes/safe/store/models/safe.js
@@ -10,7 +10,7 @@ export type SafeProps = {
   address: string,
   threshold: number,
   owners: List<Owner>,
-  balances: Map<string, string>,
+  balances?: Map<string, string>,
   activeTokens: Set<string>,
   ethBalance?: string,
 }
@@ -21,7 +21,7 @@ const SafeRecord: RecordFactory<SafeProps> = Record({
   threshold: 0,
   ethBalance: 0,
   owners: List([]),
-  activeTokens: new Set([]),
+  activeTokens: new Set(),
   balances: Map({}),
 })
 
diff --git a/src/store/index.js b/src/store/index.js
index 1e971f98..d40f5b96 100644
--- a/src/store/index.js
+++ b/src/store/index.js
@@ -15,7 +15,7 @@ import provider, { PROVIDER_REDUCER_ID, type State as ProviderState } from '~/lo
 import tokens, { TOKEN_REDUCER_ID, type State as TokensState } from '~/logic/tokens/store/reducer/tokens'
 import notifications, {
   NOTIFICATIONS_REDUCER_ID,
-  type State as NotificationsState,
+  type NotificationReducerState as NotificationsState,
 } from '~/logic/notifications/store/reducer/notifications'
 
 export const history = createBrowserHistory()