There is not much difference in price between buying a ticket in advance and on the day.
There’s no big difference in price between buying a ticket in advance and buying it on the day.
There's hardly any difference in price between buying a ticket in advance and on the day.
AとBが動詞の場合は動名詞にするといいですよ。
There is not much difference between buying a ticket in advance and on the day.
先にチケットを買っても、当日買っても違いはあまりない。
There’s no big difference between buying a ticket in advance and buying it on the day.
先にチケットを買っても、当日買っても大差はあまりない。
There's hardly any difference between buying a ticket in advance and on the day.
先にチケットを買っても、当日買ってもほとんど違いはない。
in advance: 先に
on the day: 当日
not much difference: 違いはあまりない
no big difference: 大差はあまりない
is hardly any difference: ほとんど違いはない
ご参考に！
日本 
