switch to safeParse

cw_core/lib/amount/money.dart

@@ -25,6 +25,14 @@ class Money implements Comparable<Money> {
     return Money(amount, currency);
   }
 
+  factory Money.safeParse(source, Currency currency, {bool isBaseUnit = false}) {
+    final amount = isBaseUnit
+        ? BigInt.parse(source.toString())
+        : parseFixed(source.toString().withDecimals(currency.decimals), currency.decimals);
+
+    return Money(amount, currency);
+  }
+
   /// Parse the [source] and turn it into [Money] if possible
   ///
   /// As [parse] except that this method returns `null` if the input is not

lib/view_model/buy/buy_sell_view_model.dart

@@ -171,17 +171,15 @@ abstract class BuySellViewModelBase extends WalletChangeListenerViewModel with S
     return maxAmount.toStringAsFixed(2);
   }
 
-  Money amountForQuote(Quote quote) => Money.parse(
+  Money amountForQuote(Quote quote) => Money.safeParse(
       (double.parse(fiatAmount) / quote.rate).toStringAsFixed(cryptoCurrency.decimals),
       cryptoCurrency);
 
-  Money fiatAmountForQuote(Quote quote) {
-    return Money.parse(
+  Money fiatAmountForQuote(Quote quote) => Money.safeParse(
         (fiatConversionStore.prices[cryptoCurrency]! *
                 double.parse(amountForQuote(quote).toString()))
             .toStringAsFixed(2),
         fiatCurrency);
-  }
 
   // based on usd values, should have roughly equal worth (was done with ai though so it's subject to correction)
   static final Map<FiatCurrency, List<String>> _defaultAmountsMap = {