3 files changed, 22 insertions, 3 deletions
diff --git a/packages/instant/src/util/address.ts b/packages/instant/src/util/address.ts
new file mode 100644
index 000000000..14d42d8c0
--- /dev/null
+++ b/packages/instant/src/util/address.ts
@@ -0,0 +1,6 @@
+import { web3Wrapper } from '../util/web3_wrapper';
+
+export const getBestAddress = async (): Promise<string | undefined> => {
+    const addresses = await web3Wrapper.getAvailableAddressesAsync();
+    return addresses[0];
+};
diff --git a/packages/instant/src/util/balance.ts b/packages/instant/src/util/balance.ts
new file mode 100644
index 000000000..533656858
--- /dev/null
+++ b/packages/instant/src/util/balance.ts
@@ -0,0 +1,13 @@
+import { BuyQuote } from '@0x/asset-buyer';
+import { Web3Wrapper } from '@0x/web3-wrapper';
+import * as _ from 'lodash';
+
+export const balanceUtil = {
+    hasSufficentEth: async (takerAddress: string | undefined, buyQuote: BuyQuote, web3Wrapper: Web3Wrapper) => {
+        if (_.isUndefined(takerAddress)) {
+            return false;
+        }
+        const balanceWei = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+        return balanceWei >= buyQuote.worstCaseQuoteInfo.totalEthAmount;
+    },
+};
diff --git a/packages/instant/src/util/format.ts b/packages/instant/src/util/format.ts
index ca7c01359..4a48dec9d 100644
--- a/packages/instant/src/util/format.ts
+++ b/packages/instant/src/util/format.ts
@@ -2,7 +2,7 @@ import { BigNumber } from '@0x/utils';
 import { Web3Wrapper } from '@0x/web3-wrapper';
 import * as _ from 'lodash';
 
-import { ethDecimals } from '../constants';
+import { ETH_DECIMALS } from '../constants';
 
 export const format = {
     ethBaseAmount: (
@@ -13,7 +13,7 @@ export const format = {
         if (_.isUndefined(ethBaseAmount)) {
             return defaultText;
         }
-        const ethUnitAmount = Web3Wrapper.toUnitAmount(ethBaseAmount, ethDecimals);
+        const ethUnitAmount = Web3Wrapper.toUnitAmount(ethBaseAmount, ETH_DECIMALS);
         return format.ethUnitAmount(ethUnitAmount, decimalPlaces);
     },
     ethUnitAmount: (
@@ -36,7 +36,7 @@ export const format = {
         if (_.isUndefined(ethBaseAmount) || _.isUndefined(ethUsdPrice)) {
             return defaultText;
         }
-        const ethUnitAmount = Web3Wrapper.toUnitAmount(ethBaseAmount, ethDecimals);
+        const ethUnitAmount = Web3Wrapper.toUnitAmount(ethBaseAmount, ETH_DECIMALS);
         return format.ethUnitAmountInUsd(ethUnitAmount, ethUsdPrice, decimalPlaces);
     },
     ethUnitAmountInUsd: (