diff --git a/lib/buy_account_credit_form.rb b/lib/buy_account_credit_form.rb
index 1c3cca0519184be1713d82a8be782c90d2f64091..b6a1da671cb6c4c17886ed433c7dc2ff56e5a828 100644
--- a/lib/buy_account_credit_form.rb
+++ b/lib/buy_account_credit_form.rb
@@ -3,10 +3,7 @@
 class BuyAccountCreditForm
 	class AmountValidationError < StandardError
 		def initialize(amount)
-			super(
-				"amount #{amount} must be in the range " \
-				"#{RANGE.first} through #{RANGE.last}"
-			)
+			super("amount #{amount} must be more than $15")
 		end
 	end
 
@@ -21,20 +18,18 @@ class BuyAccountCreditForm
 		@payment_methods = payment_methods
 	end
 
-	RANGE = (15..1000).freeze
-
 	def form
 		FormTemplate.render(
 			:top_up,
 			balance: @balance,
 			payment_methods: @payment_methods,
-			range: RANGE
+			range: [15, nil]
 		)
 	end
 
 	def parse(form)
 		amount = form.field("amount")&.value&.to_s
-		raise AmountValidationError, amount unless RANGE.include?(amount.to_i)
+		raise AmountValidationError, amount unless amount.to_i >= 15
 
 		{
 			payment_method: @payment_methods.fetch(